The Moyal quantization is described using difference analogues of vector fields whoseLie brackets play the role of Heisenberg commutators.

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The zero-temperature magnetization curve of the S=1 antiferromagnetic XXZ chain with partial integrability is studied by the Bethe ansatz, combined with a numerical renormalization-group method. We find a magnetic first-order phase transition; the magnetization curve shows a discontinuity at a critical field h_c. Due to the partial integrability, the low-field curve and the high-field curve each correspond to a part of the magnetization curve of the S=\frac12XXZ chain. We conclude that the obtained magnetization curve is exact in the whole range of the magnetic field.

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A stable, 1.13, MW single-mode oscillation was obtained at 170, GHz in a short-pulse gyrotron with a high-order volume mode TE_{31, 8}. The maximum efficiency was 30 %, and no power degradation due to mode competition was observed. This result indicates the potential for the development of a 170, GHz, 1, MW, CW gyrotron which is required for electron cyclotron heating and current drive of large fusion devices.

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Recent experiments have demonstrated strong nonlocal effects in tokamaks, that apparently cannot be explained by conventional transport theories. In this letter the observed rapid changes in temperature are interpreted on dynamical grounds, by analyzing the adiabatic response, under an appropriate global constraint, of a certain family of axially invariant modes to an externally produced change of the current density at the edge.

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When a chemical reaction such as A ⇔ B takes place simultaneously with a macrophase separation, mesoscopic structures similar to the patterns emerging during microphase separation appear.Since in a chemical system we can easily control the concentrations of the two species and reaction rates and so on, a greater variety of domain morphology is expected.We demonstrate some of the new morphologies by computer simulations.

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Longstanding puzzles on the Fermi surfaces in CeB₆ and PrB₆ have been resolved in a combined theoretical and experimental study. In CeB₆, even after a metamagnetic transition, no up or down spin splitting occurs, except a small split on the small pocket surface. The heavier mass branch can be seen only by acoustic de Haas van Alphen measurement. In this case, the observed effective mass is consistent with the large T-linear specific heat. In PrB₆, the splitting can be seen on all the branches but in the opposite sense, that is, the larger-area branch is observed as the smaller-area branch. Combined with the crossover characteristics of the pocket band, the puzzle of a pocket which is too large compared with the neck size is solved.

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The single-particle spectral functions for the two-dimensional t-J model are investigated in connection with spin and charge dynamics, using the exact diagonalization technique. At low electron density, Fermi liquid behavior is observed. Near half-filling, the spectral functions reveal a two-peak structure which is due to the different dynamics of spin and charge degrees of freedom. This density dependence of the spectral functions indicates a crossover from Fermi liquid behavior at low density to anomalous behavior near the Mott transition where the approximate decoupling of spin and charge excitations occurs.

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We measured the temperature dependence of the resistance of ultrasmall Al single tunnel junctions. NiCr thin films or multiple junctions were used to fabricate measuring leads with lead resistance higher than the resistance quantum R_K = h/e^2=25.8 , kΩ. We observed the superconductor-insulator (SI) transition in single tunnel junctions for the first time. The critical normal-state resistance of the SI transition is determined to be about 11, kΩ. The use of high-resistance leads was indispensable, since a low lead resistance prevents observation of the intrinsic nature of single junctions at low temperatures. We claim that this SI transition is a manifestation of the dissipative phase transition which is predicted to occur in Josephson junctions with strong dissipation.

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We report the first measurement of Hall effect and thermoelectric power (S) in multilayers prepared on a V-groove microstructured substrate for current-at-an-angle-to-plane (CAP) geometry to extract the contribution from the current-perpendicular-to-plane (CPP) geometry. In the field dependence of extraordinary Hall resistivity (ρ _H^M), we found a clear difference between CAP and current-in-plane (CIP) geometries. In contrast, ρ _H^M values at saturation field are almost the same despite the large difference in the resistivity (ρ ) between the two geometries. From the comparison of the results for two samples with different layer thicknesses, the ratio of the average mean free path of conduction electrons to the layer thickness was found to play an essential role in the scaling relations between ρ _H^M(S) and ρ .

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In investigation of commensurability oscillations in antidot lattices, we find a relation between the resistivity ρ_xx and the differentiated Hall resistivity dρ_xy/dB, where B is the strength of the magnetic field. All peaks of ρ_xx exactly correspond to those of dρ_xy/dB.This coincidence is direct evidence that the extended Drude model for the oscillations cannot fully explain the magnetoresistance experimentally observed in antidot lattices.

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The magnetoresistance of a silver loop, a part of which was replaced by superconducting aluminum, was measured. The h/2e conductance oscillations whose amplitude increased to about 400(e²/h) at T=0.1, K were observed. The samples exhibited nonlinear I-V characteristics at low temperatures and the oscillations were inverted when the current was increased. The anomalous negative magnetoresistance was also observed at low fields at the lowest temperatures.

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We study the electronic states of graphite ribbons with edges of two typical shapes, armchair and zigzag, by performing tight binding band calculations, and find that the graphite ribbons show striking contrast in the electronic states depending on the edge shape. In particular, a zigzag ribbon shows a remarkably sharp peak of density of states at the Fermi level, which does not originate from infinite graphite. We find that the singular electronic states arise from the partly flat bands at the Fermi level, whose wave functions are mainly localized on the zigzag edge. We reveal the puzzle for the emergence of the peculiar edge state by deriving the analytic form in the case of semi-infinite graphite with a zigzag edge. Applying the Hubbard model within the mean-field approximation, we discuss the possible magnetic structure in nanometer-scale micrographite.

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Electrical resistance of Ca is measured under pressures up to 150, GPa and at temperatures down to 0.05, K. Superconductivity is observed at temperatures below 3, K under pressures above 85, GPa. The superconducting transition temperature increases linearly with increasing pressure and reaches about 15, K at 150, GPa.

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The mechanism responsible for determining the exchange interaction to be ferromagnetic orantiferromagnetic in Cu²⁺ compounds is closely correlated withthe antiferrodistortive (AFD) or ferrodistortive (FD) order of Cu²⁺ hole orbitals.One of the representative two-dimensional Heisenberg ferromagnets, K₂CuF₄, has an ideal AFD orbital ordering. To investigate the possibility of the magnetic phase transitiondue to a change in the orbital ordering from AFD to FD at high pressures, susceptibility measurements of this compound have been made under various pressuresup to 13, GPa over the temperature range from 1.5 to 18, K.A sudden decrease in the Curie temperaturestarting from 7, GPa was observed. Furthermore, a large decrease in the susceptibility was observedat pressures above 10, GPa. These results indicate a pressure induced ferromagnetic to antiferromagnetic phase transition occurring at about8--9, GPa as a result of a change of orbital state fromAFD to FD order.

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In this article we discuss the reflection positivity in spinspace for the Heisenberg model and the Kondo Hamiltonian. We show thatthe ground state is unique for J≠0 where J is the strength of theexchange interaction in the Heisenberg model or the exchange couplingbetween the localized spins and conduction electrons in the Kondo model.We introduce the Coulomb interaction U>0 between the conductionlectrons for the Kondo Hamiltonian to show the uniqueness of the groundstate. We write the Hamiltonian in terms of fermions to express the exchangeinteractions and impose constraints. We employ the Lagrange-multipliermethod to deal with the constraints in this work.

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Magnetic susceptibility of an organic ion-radical salt, [3, 3^′-dimethyl-2, 2^′-thiazolinocyanine]-TCNQ, is measured in the temperature range of 1.4--300, K. Above 10, K, it is quantitatively explained in terms of a S=1/2 Heisenberg antiferromagnetic chain with J/k_B=-32.5, K based on the Bonner-Fisher curve. Below 10, K, however, the measured susceptibility seems to show the characteristic slope reported by Eggert et al. down to the ordering temperature T_c=1.49, K. Below T_c the heat capacity of this salt displays the temperature dependence expected for a gapless spin-wave excitation, which rules out the spin-Peierls transition in this system.

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The field-induced magnetic transition in GdSi has been investigated. The Néel temperature and the paramagnetic Curie temperature are 55, K and -8, K, respectively. The metamagnetic transition occurs at a magnetic field of 197, kOe at 4.2, K. The critical field of the metamagnetic transition decreases linearly with the square of temperature T². For the GdM (M=Si, Al and Ge) equiatomic compounds, the linear relationship between the critical field and the Néel temperature has been confirmed.

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Neutron inelastic scattering studies have been performed on the quasi-two-dimensional spin-gap system CaV₄O₉. An energy gap of about 10, meV has been clearly observed in the magnetic excitation spectra at low temperatures. The Q-point of the minimum excitation energy may not correspond to the so-called (π, π ), (π, 0) or Γ -points in the reciprocal cell of the two-dimensional tetragonal lattice. With decreasing temperature, the scattering intensity in the energy region around 12, meV begins to increase at about 100, K, which almost coincides with the temperature at which the susceptibility has a maximum value. This result may provide important information to understand the “spin-gap anomaly” of high-T_c oxides.

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The magnetic properties of the S=1/2 double spin chain system KCuCl₃ have been investigated by susceptibility measurements using single crystals. It is found that the susceptibilities for three different external field directions exhibit broad maxima at around 30, K and decrease exponentially to zero with decreasing temperature. This result indicates that the ground state of KCuCl₃ is nonmagnetic and there is a finite gap in its excitation spectrum. This behavior is attributable to the quantum effect characteristic of the double spin chain. The structure of the exchange couplings in the double chain is discussed. Applying the recent spin ladder theory, we estimate the magnitude of the excitation gap to be Δ/k_B=35, K.

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Effects of nonmagnetic impurity doping in a spin ladder system with a spin gap are investigated by exact diagonalization andvariational Monte Carlo calculations.Substantial changes in macroscopic properties such as enhancements in spin correlations and magnetic susceptibilities are observed in the low impurity concentration region, which are due to an increase of low-energy states. These results suggestthat a small but finite amount of nonmagnetic impurity dopingcauses reduction or disappearance of the spin gap.This qualitatively explains the experimental resultsfor Zn-doped SrCu₂O₃ in which a small amount of doping results in disappearance of the spin gap.We propose a possible scenario for this marked changeas a quantum phase transitionin a spin-gap ladder system due to spinon doping effects.

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We report Cu NMR and NQR studies of the cupric sulfide CuS from 4.2, K to room temperature. We have assigned the site for two distinct ⁶³Cu NMR lines based on an abrupt change of the Cu NMR spectrum at 55, K due to a structural phase transition for both the powder and the oriented CuS. We found that the Cu nuclear spin-lattice relaxation rate 1/T₁ is magnetic in origin and highly anisotropic, and that the temperature dependence of 1/T₁T is similar to that of the uniform magnetic susceptibility χ ₀(T). The orbital contribution to the relaxation rate and the nature of the electron spin correlation at the Cu sites are discussed.

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By utilizing a far infrared laser operating in the THz range, we have observed new electron spin resonance (ESR) lines in the ordered states of a layered antiferromagnet with strong uniaxial anisotropy, FeBr₂. We interpret these ESR lines as arising from transitions within the lowest triplet state of single Fe²⁺ ions. Good agreement between theory and experiment is obtained without any adjustable parameters.

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Dielectric, AC calorimetric and X-ray investigations were carried out for a single crystal of (CH₃)₂NH₂H₂PO₄. The specific heat shows a λ -type anomaly associated with a phase transition at the Curie temperature of 259.15, K ( T_c ).A large dielectric anomaly was observed at T_c and a D-E hysteresis loop was observed below this temperature.It was found that the crystal undergoes a second-order phase transition and becomes ferroelectric below T_c .The results of X-ray examination indicate that the crystal belongs to monoclinic P2₁/n with the lattice parameters of a =9.290(1), Å, b =9.592(3), Å, c =7.001(1) , Å and β =90.35(3)° at room temperature, and to Pn with a =9.267(4) , Å, b =9.560(1) , Å, c =6.988(2) , Å and β =90.42(3)° at 193, K.

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Two pressure-induced ferroelectric phases are found for [N(CH₃)₄]₂CuCl₄ crystal within the pressure-induced incommensurate phase. One exists above about 200, MPa in a narrow temperature region just above the upper boundary of the lock-in commensurate phase with the c-lattice parameter tripling. Another one appears above about 250, MPa at higher temperatures, and expands with increasing pressure. The spontaneous polarization develops along the b-direction in both ferroelectric phases. The pressure-temperature phase diagram including the newly observed ferroelectric phases is shown, and the mechanism of the ferroelectricity is discussed.

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We investigate the interaction between a pair of domain boundaries in a Bonhoffer-van der Pol type reaction diffusion system in one dimension. An interfacial approach is applied to study the stability of a pair of domain boundaries upon collision. A general form of the interface equation of motionis derived and the condition is obtained for which boundaries do not annihilate upon collision but behave as if they are elastic objects. Computer simulations are also carried out to confirm our prediction.

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Dromions are exact, localized solutions of (2+1) dimensional evolution equations and decay exponentially in all directions. `Solitoffs' of the Davey-Stewartson equations constitute an intermediate state between dromions and plane solitons, since they decay exponentially in all directions except a preferred one. Here solitoffs are rederived by the Hirota bilinear operator and extended to a variety of nonlinear evolution equations.

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Two-colour aperiodic planar patterns with five-fold, seven-fold and eight-fold symmetries are interpreted as words sequences of D0L Systems. Substitutional sequences for the edges of the basic tiles are also given. Recursion relations for the Fourier amplitudes can be obtained by using an equivalent geometric description for the generation of the patterns.

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Generalizing Zhang's method, we construct the quantum Lax pair of the one-dimensional Hubbard model from the Yang-Baxter relation.

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We report Monte-Carlo simulations of a model for a self-avoiding randomly tethered membrane. By changing the referencce bond length b, we have studied two cases of “weak” self-avoidance (b=3.0) and “strong” self-avoidance (b=1.7). The membrane with strong self-avoidance is asymptotically flat and its shrinkage is small as compared with the membrane without disorder. On the other hand, in contrast to our preliminary result [S. Mori, Phys. Lett. A 207 (1995) 87], the membrane with weak self-avoidance isin a crumpled phase with a large shrinkage. The exponent ν for the radius of gyration (R_G-- L^ν) is found to be ν=0.87 ± 0.02. We discuss the implications of the result, in particular its relevance to the understanding of the wrinkling transition in partially polymerized vesicles.

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Making use of the transfer matrix method, the Trotter number dependence of the magnetization is studied for various Heisenberg chains includingthe trimerized model which has ferromagnetic-ferromagnetic-antiferromagnetic exchange couplingconstants along the chain. In the trimerized modelthe dependence on the Trotter number is found to be nonmonotonic andit warned that extrapolations from small Trotter numbers result inspurious wrong behavior.We discuss the relation between the nonmonotonicity and ground state phase transition of the system.We also propose an alternate extrapolation method in a Legendre transformed variable.

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One-dimensional asymmetric exclusion model, in whichthe probabilities of hopping to the left and right are in general different, is studied. The boundaries are open; a particle is added at the left end and is removed at the right end. First, the mean field theory is applied to discuss the case ofarbitrary hopping probabilities. Second, exact solution is obtained for the case of equal hoppingprobability. Third, the properties of the model near the equal hopping probability case are investigated by the perturbation theory.It is found that the mean field theory does not give the correctdensity profile near the boundaries.

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We study exact solutions of thefour-point correlation functions around a vertex of the anti-ferroelectric six-vertex model. After showing thatan expression for the correlations is readily obtained by differentiating theknown exact solution of the free energy, we present a new expression for the correlationsderived through the recently developed vertex operator approach.It has the form of a double contour integralof a meromorphic function.To give a new verification of the vertex operator approachbeyond the case of the one-point function, we prove the equality of the two expressions by calculating thecontour integrals.

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Properties and possible applications of ultra-short (femto- to pico-second) electromagnetic mono- and sub-cycle waves are studied. First, the structural characteristics of these waves are examined. Transient pulses of circularity polarized waves have more complicated structures than those of plane polarized ones. In addition, a pair of colliding pulses may locally and instantaneously generate purely electric or magnetic fields. A general method is presented to describe linear characteristics of these waves propagating through some homogeneous, dispersive media such as air, plasma and optical fibers. Although their spectra are ultra-wideband, should their time duration be short enough, these pulses can in some cases propagate through dispersive media for relatively long distances, approximately maintaining their original waveforms. In particular, such pulses traveling in a plasma shows a characteristic quite opposite to that of ordinary wave packets.

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The flow around a source doublet in a two-dimensional shear flow along a flat plane is investigated analytically with an incompressible inviscid fluid. The velocity field is obtained by the linearized Euler equation. It is shown that the shear suppresses the three-dimensionality of the disturbance and makes the flow be rather two-dimensional one that parallel to the plane. A deformed vortex line consists of the looped line and the straight line of the shear flow.

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Buoyancy-contributing turbulence is investigated from a viewpoint of the turbulence modellingwith an aid of a two-scale direct-interaction approximation (TSDIA). Applying the spectralinertial-range form to the second-order analysis of the TSDIA, the ensemble-meanrepresentations for the Reynolds stress, the heat flux, and model equations for theturbulent-energy and thermal-intensity dissipation rates are derived and discussed in detail.

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Fully nonlinear time evolution of periodic capillary gravity waves on an inviscid fluid of infinite depth is investigated numerically.The cases where the effect of surface tension is weaker than that of gravity are considered.It is found that the weakly resonant symmetric steady waves are unstable to two kinds of disturbances: the sidebands and the higher harmonics.Ripples are generated within a time of a few periods.They first appear at the point with the greatest slope on the forward face of the highest crest of the disturbed steady waves.

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Vibration of a water drop placed on a vertically oscillating plate was observed, and the amplitudes and frequencies of the plate were measured with which the drop showed large amplitude vibrations. A special cloth was used so that the drop did not wet the plate. The results are compared with a simple theoretical prediction based on the Mathieu equation. The experimental data are shown to lie within the unstable growing region derived from the theory.

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Pattern selection phenomena in parametrically excited surface waves are studied by the weakly-nonlinear system of three modes derived by the average Lagrangian method. The third-order coefficients of nonlinear interaction between two line patterns intersecting at an arbitrary angle are obtained in the gravity-capillary waves of arbitrary depth. Classification, stability analysis and bifurcation study of the fixed points of the dynamical equations with linear damping are performed in the cases of three symmetric line modes and general modes. Investigating the stability of various patterns to the disturbance of line mode with an arbitrary intersecting angle and the internal stability, it is shown that squares are the most preferred pattern in capillary waves, while lines are selected in gravity waves.

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A direct experimental evidence was given for that high-power broadband microwaves radiated from the plasma at the injection of an intense relativistic electron beam strongly correlates to the electric fields in cavitons induced in the plasma. This radiation did not increase linearly with the field energy density in cavitons, which differed from the trend in accordance with the collective Compton boosting model.

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Protuberances in the axial direction in an ion saturation current created by microwave pulses externally injected into a plasma-filled corrugated wall waveguide are observed experimentally. This phenomenon is observed for moderately high microwave powers above a threshold value. Such protuberances are not observed in smooth cylindrical plasma waveguides. Protuberances in the axial density profile and peaks in the standing waves of the axial RF electric field are always observed at identical axial positions, at which the radius of the corrugated wall is minimum. A physical interpretation of the observed results is discussed in detail.

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The F-Θ diagram and average beta valuesof a finite-pressure plasma in a toroid are consideredby the use of the equilibrium configuration of a reversed field pinch (RFP)reported recently.Here F is the field reversal ratio, Θ is the pinch parameter, and beta values mean the ratio of the plasma pressure to the magnetic pressure. The equilibrium is a generalization of the force-free field model.The F, Θ and beta values averaged over the plasma cross section are derived.The F and average beta values obtained here are graphically shownas a function of Θ. It is found that the results agree with experimental findings.

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Crystal structure of RbCN has been investigated on single crystals by X-ray precession photographic method at temperatures ranging from 300 to 85, K. At about 125, K, the crystal transforms from the cubic NaCl-type phase into a low-temperature phase in which a monoclinic and a triclinic forms coexist. Both the forms are related with the specific crystallographic orientation to the cubic lattice. The lattice constants of the monoclinic form are a_M=4.81(1), b_M=4.87(1), c_M=7.92(1), Å, β =122.7(1)° at 85, K, and the structure is A-base-centered with the space group A2/m. The lattice constants of the triclinic form are a_T=9.79(1), b_T=4.62(1), c_T=4.88(1), Å, α =121.1(1)°, β =119.4(1)°, γ =90.0(1)° at 85, K. Crystallographic relationships between these forms and the cubic form are presented. The results are compared with the findings in the related compound KCN.

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Neutron diffraction measurements in liquid Tl_xS_1-x alloys with x=0.67, 0.57, 0.50, 0.33 and 0.29 have been carried out to obtain theirshort-range structures. For the comparison, the amorphous structure ofthe alloys with 0.50 ≥q x ≥q 0.29 has been investigated also throughX-ray diffraction measurements. The liquid alloy has a chemicalorder relating to the crystalline phase at x=0.67 (corresponding tothe composition of Tl_2S), where the metal-nonmetal transition occurs.The liquid structure at the rest four compositions is considerablydifferent from the corresponding crystalline one.Consequently, two distinct chemical orders appearin the composition range between Tl_2S and S in the liquid state, i.e., theTl_2S-like chemical order and sulfur linkage unit. On the other hand, crystalline chemical orders are rather retained in the amorphous state, for example, TlS_4/2 tetrahedra in crystallineTlS and Tl_2S_5 molecular units in crystalline Tl_2S_5 have beenobserved also in the amorphous state.

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In this article, we derive a strongly nonlinear evolution equation by usingthe integral method to study the instabilities in a directionallysolidified binary mixture. This equation not only can describe the interfacialbehaviors of all the long-wave limits, but also can provide the possibility ofstrongly nonlinear instability analysis.Three-dimensional weakly nonlinear analysis proceeded from the criticalcondition is undertaken to investigate the two-dimensional bend-like cells andthe three-dimensional hexagonal structures.

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The successive phase transitions in the ferro- and antiferro-electric smectics have been described by the Ising model with competing interactions. The additional pseudo-spins are introduced newly to represent the sense of the molecular long axis. By taking the sum over the whole states of these pseudo-spins in the partition function, not only the nearest neighbour parameter of the Ising model are renormalized but additional long range interactions and many-body forces are shown to be induced. The effective second nearest neighbour interaction is shown to be antiferroelectric kind and the third nearest neighbour one is ferroelectric in some cases. In the ferroelectric phase and main antiferroelectric one the sense of the molecules is arranged such that the ordering is absent even in the ordered region in agreement with the symmetry of these phases, while in the other intermediate phases this ordering is proved to exist because of the bias due to the stacking of layer-orders.

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Density and sound velocity measurements have been made to investigate the thermodynamic properties of the liquid Bi--Se system. The molar volume and isothermal compressibility have been deduced as a function of composition which show large negative deviation from the ideal behaviour. The results suggest that Bi₂Se₃ assembly having a densely packed structure causes semimetallic nature of this system.

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Various types of superfluid-insulator transitions are investigatedfor two-component lattice boson systems in two dimensionswith on-site hard-core repulsion andthe component-dependent intersite interaction.The mean-field phase diagram is obtained by the Gutzwiller-type variational technique.Various ground-state properties are also studiedby the quantum Monte Carlo method.Our model exhibits two types of diagonal long-range orders;the density order around the density n=1/2 and the Ising-type component order near n=1.In contrast to the Gutzwiller results, the Monte Carlo results show thatthe continuous growth of the component correlationseverely suppresses the superfluidityas well as the inverse of the effective massin the critical region of the component order transition.We propose a mechanism of this mass enhancement observedeven far from the Mott insulating filling n=1, when the Ising-type component order persists into n ≠ 1.Possible relevance of this type of mass enhancement in other systemsis also discussed.

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We study wandering instability of an isolated step in a surface diffusion field with a direct electric currentapplied perpendicular to the step.The drift of adatoms caused by the electric currentmodifies the surface diffusion length.In sublimation the difference between the modified surface diffusion length in the upper terrace and that in the lowerterrace causes an instability with respect to fluctuation along the step.This instability occurs when the drift is opposite to thestep motion and its strength is within a limited range.Near the lower critical current the step obeys theKuramoto-Sivashinsky equation, which gives rise to spatiotemporal chaos.

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The P Kβ emission and S Kβ emission spectra influorescence from the layered compounds MPS_3 (M = Mn, Fe, Ni, Zn, Mg)have been measured with a high-resolution two-crystal vacuumspectrometer equipped with Ge(111) crystals. The measured emissionspectra are mainly determined by the [P_2S_6]^4- cluster. TheP Kβ emissionand S Kβ emission spectra of ZnPS_3, NiPS_3 and FePS_3are compared with available XPS valence-bandspectra and theoretical band structures on a common energyscale and their valence-band structuresare investigated. It is shown that the P 3p and S 3pstates in their valencebands lie very close to each other and the respective 3p statesare alike in the MPS_3 compounds.

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The effects of on-site Coulomb interaction in two-dimensional organic conductors, κ-(BEDT-TTF)_2X, α-(BEDT-TTF)_2I_3 and (BEDT-TTF)_2MHg(SCN)_4, have been studied within the Hartree-Fock approximation. If the strength of Coulomb interaction exceeds some critical value, various kinds of antiferromagnetic states appear and these phases have been classified on a phase diagram with two key parameters, which leads to a unified view on the ground states of this unique family.

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