We present a study of electronic transport in individual Bi nanowires of large diameter relative to the Fermi wavelength. Measurements of the resistance and thermopower of intrinsic and Sn-doped Bi wires with various wire diameters, ranging from 150-480 nm, have been carried out over a wide range of temperatures (4-300 K) and magnetic fields (0-14 T). We find that the thermopower of intrinsic Bi wires in this diameter range is positive (type-p) below about 150 K, displaying a peak at around 40 K. In comparison, intrinsic bulk Bi is type-n. Magneto-thermopower effects due to the decrease of surface scattering when the cyclotron diameter is less than the wire diameter are demonstrated. The measurements are interpreted in terms of a model of diffusive thermopower, where the mobility limitations posed by hole-boundary scattering are much less severe than those due to electron-hole scattering.
@article{arxiv.0711.0010,
title = {Diameter-dependent thermopower of Bi nanowires},
author = {A. Nikolaeva and T. E. Huber and D. Gitsu and L. Konopko},
journal= {arXiv preprint arXiv:0711.0010},
year = {2009}
}
Comments
32 pages, 12 figures. Previous version replaced to improve readability