PHONON-DRAG THERMOPOWER OF A BALLISTIC QUANTUM-WIRE

The phonon-drag thermopower S-g of a quasi-one-dimensional ballistic q uantum wire is calculated by using the Onsager relation to relate S-g to the phonon-drag contribution to Q/Delta V, where Q is the heat flux produced by a small voltage difference Delta V across the wire. A gen eral formula is derived for S-g and numerical results are presented fo r when two electronic subbands are involved. The dependence of S-g on the wire width exhibits peaks similar to those Shown by the diffusion thermopower S-d. It is found, however, that the S-g maxima are up to 5 0-100 times larger than the corresponding ones for S-d when T=1-10 K. The dominance of S-g is apparent for all the values of the wire width and temperatures investigated. [S0163-1829(97)51040-X].