J. Phys. I France 6 (1996) 2135-2140
Dielectric Voltage Response in Spin-density Wave of (TMTSF) AsF at Low TemperatureMitsuharu Nagasawa
Department of Physics, Hokkaido University, Sapporo 060, Japan
(Received 26 April 1996, revised 19 August 1996, accepted 20 August 1996)
Voltage response to constant unipolar pulse current in the spin-density wave (SDW) state of (TMTSF) 2AsF 6 was studied. Below 3 K, leading and tailing edges of the voltage response are rounded at low electric field. The time dependent charge density accumulated in the lattice was estimated from the voltage profiles. It can be fitted by a stretched exponential formula; . With increasing field q0 increases and shows a maximum at the threshold electric field for depinning. In the pinned state, the relaxation time increases with decreasing temperature and its activation energy is approximately equal to that of ohmic conductivity. The index is a linearly decreasing function of temperature and it is extrapolated to one at 0 K. Screening by normal carriers becomes imperfect and coupling between density wave domains becomes stronger on cooling.
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