Uniaxial strain and anisotropy in the spin density wave in (TMTSF)2PF6

The temperature-uniaxial pressure (T-P) phase diagram of metal, spin density wave in (TMTSF)(2)PF6 was apparently quite similar to that of hydrostatic pressure irrespective of the direction of the uniaxial pressure in strain method. However, by the examination of rho(a), rho(b') and rho(c*) under three uniaxial pressures, it was found that the anisotropy was similar between hydrostatic and a-axis-uniaxial pressure. The strain along b' and c*-axes reduces the anisotropy strongly, i.e. t(a)/t(b') = 4.3 with p//c* = 10 kbar, for instance, where still spin density wave is present. Although a-compression seems to vary the anisotropy similarly to that of the hydrostatic pressure, the so-called rapid oscillation was not observed under a-compression but under the hydrostatic pressure. This result implies that the effect of a-compression is still different from that of the hydrostatic pressure. We discuss how our result is related with the electron correlation. (C) 2002 Published by Elsevier Science Ltd.