Physical Review B 60, 13648 (1999)

Từ Thư viện Khoa học VLOS
Bước tới: chuyển hướng, tìm kiếm
Semiclassical approach to the density of states of the disordered electron gas in a quantum wire
Semiclassical approach to the density of states of the disordered electron gas in a quantum wire
 Tạp chí Physical Review B 1999 15 November 1999; 60 (19):13648
 Tác giả   Doan Nhat Quanga and Nguyen Huyen Tungb
 Nơi thực hiện   a Center for Theoretical Physics, National Center for Natural Science and Technology, P.O. Box 429 Boho, Hanoi 10000, Vietnam

bInstitute of Engineering Physics, Hanoi University of Technology, 1 Dai Co Viet Road, Hanoi, Vietnam

 Từ khóa   quantum wire, density of state, disorder
  DOI   URL  PDF

Abstract

A theory is given of the density of states (DOS) of the quasi-one-dimensional electron gas (1DEG) in a semiconductor quantum wire in the presence of some random field. For a smooth random field, the derivation is carried out within Gaussian statistics and a semiclassical model. The DOS is then obtained in a simple analytic form, where the input function for disorder interaction is the autocorrelation function of the random field. This allows one to take completely into account the geometry of the wire, the origin of disorder, and the many-body screening by 1D electrons. The DOS is demonstrated to be composed of the classical DOS and the quantum correction, which are connected with fluctuations in the random potential and in the random force, respectively. The disorder is found to smear out the square-root singularity of the DOS of the ideal 1DEG into a finite peak tailing below the subband edge. The disorder effects from impurity doping and surface roughness on the DOS of the 1DEG in a cylindrical GaAs wire of radius R are thoroughly examined. It is shown that for $R<\leq a*/2$ (with a* as the effective Bohr radius) surface roughness with a radius fluctuation equal to 10% of R overwhelms impurity doping with a density ni=106cm-1, but for $R\geq a*$ the latter is dominant.