EFFECT OF PRESSURE ON THE CHARGE-DENSITY WAVE TRANSITIONS IN ETA-MO4O11 CRYSTAL

Electrical resistivity Q versus temperature T over 4.2 to 300 K under hydrostatic pressures up to 1.2 GPa, transverse magnetoresistance, and Hall effect at 4.2 K and constant pressure are measured for a quasi-two-dimensional crystal of monoclinic eta-Mo4O11. Semiempirical analysis of the Q-T curves below the charge density wave (CDW) transition temperatures T(c1) and T(c2) shows that the temperature dependences of the CDW gap energies DELTA-1 (T) and DELTA-2 (T) follow a single universal curve, independent of applied pressures. The Shubnikov-de Haas oscillations are also observed in these transport quantities, from which the effect of pressure on the nature of Fermi surfaces of holes and/or electrons associated with the CDW transitions is discussed qualitatively.