抄録
Stimulated, interband Landau emission originating from excitation of electrons and holes by the action of the J×H force at the quantum limit has been observed, accompanied by a remarkable current saturation in the V-I curve, for the first time in bulk n-type InSb at 4.2–135 K when passing a current density J as low as 16–40 A/cm2 in perpendicular to a magnetic field H up to 7 T. Such an outstanding low value of the critical current density Jc for lasing is considered to originate from extremely high value of the density of states of electrons populated in the lowest Landau level at the quantum limit. In addition to the tunability of the emission frequency controlled primarily by the magnetic field, lowering of Landau levels, which results in a virtual decrease of the energy gap of about 20 meV at around Jc for H=7 T, has also been observed in proportion to the current densities. The lowering of Landau levels can be interpreted in terms of the action of the strong electric field induced along J×H direction.
