Abstract
The Hall effect was studied in β-(BEDT–TTF)2I3 in order to survey the problem of the low-Tc and the high-Tc states and the general interest to the Fermi surface of this material. i) Our measurement revealed that this material is a metal with almost constant hole numbers down to 20 K. By the estimate of RH=1⁄nec, the hole number seems to be less than one per unit cell. ii) In the temperature dependence of RH in detail, we found a pronounced stepwise decrease by 8% in Hall voltage when temperature is lowered through 175 K but not through 110 K. iii) Further, below 20 K, Hall voltage was found to decrease. Possible reasons for such phenomena are discussed.
