Semiconductors

Anderson localization and the pseudogap in the energy spectrum of holes in PbTe: Tl under resonant scattering

S. A. Nemov^ab, Yu. I. Ravich^a, R. V. Parfen'ev^b, D. V. Shamshur<sup>b

a</sup> St. Petersburg Polytechnic University
^b Ioffe Institute, St. Petersburg

Abstract: This paper reports on a comprehensive study of the effect of additional doping with the Na acceptor impurity on the low-temperature resistivity of PbTe samples doped with Tl (2 at%), an impurity producing a band of resonant states within the valence-band spectrum. By additional doping with Na, we have shifted the Fermi level within the band of the resonant states of Tl in PbTe and varied the hole filling $(k_h)$ of the thallium impurity states. The larger part of the PbTe: (Tl,Na) samples transfers to the superconducting state with a critical temperature $T_c$ = 0.4–2.3 K. The $T_c(k_h)$ relation obtained argues for the fact that, in the region of resonant states in PbTe: Tl, Anderson localization of holes and a pseudogap in the density of delocalized states are observed.

Received: 11.10.2010

 English version: Physics of the Solid State, 2011, 53:5, 936–938

Bibliographic databases:

•