Thermopower study of (tmtsf)2asf6 sdw state

The thermoelectric power of (TMTSF)2AsF6 was measured along the a-axis. A thermal hysteresis was found in the SDW state. Effects of magnetic fields were investigated for the field direction parallel to the a-, b′and c*-axes, where b′ is defined as being perpendicular to both the aand c*-axes. There was no magnetic hysteresis nor magnetic field influence on the thermal hysteresis. Suggestion is made about random pinning of SDW or structural changes accompanying SDW transition or both being origin of this phenomenon. The temperature and magnetic field dependence of the thermopower suggests the presence of subphases of SDW divided by T1 = 2 K and T2 = 4.5 K.