Double-well model of dielectric relaxation current

摘要

We show that a straightforward account of dielectric relaxation current in glasses follows from a semiclassical treatment of the double-well model [P. W. Anderson, B. I. Halperin, and C. M. Varma, Philos. Mag. 25, 1 (1972) and W. A. Phillips, J. Low Temp. Phys. 7, 351 (1972)] explaining the linear specific heat of glasses at low temperature. The current is obtained from the field-induced tunneling of the glass between the minima of its potential energy surface, and is found to have the experimentally observed linear dependence on field and inverse dependence on time. The effects of temperature and prior biases are briefly discussed, as well as the relation of the model to the theory of charge trapping. No dielectric relaxation is expected in a perfect insulating crystal, raising the important technological question of how perfect high-k dielectrics like HfO_(2) and ZrO_(2) must be in order to serve as gate dielectrics in transistors.