Chemical and magnetic impurity effects on electronic properties of semiconductor quantum wires

TL;DR

This paper theoretically investigates how chemical and magnetic impurities affect the electronic states in semiconductor quantum wires, revealing impurity-induced band shifts, suppression of singularities, and band broadening depending on impurity type and concentration.

Contribution

It introduces a theoretical model analyzing impurity effects on electronic properties of semiconductor quantum wires using the coherent potential approximation.

Findings

Nonmagnetic impurities shift the carrier band and suppress van Hove singularities.

Magnetic impurities broaden the band and can eliminate singularities at high concentrations.

Impurity effects depend on concentration and exchange coupling strength.

Abstract

We present a theoretical study of electronic states in magnetic and nonmagnetic semiconductor quantum wires. The effects of chemical and magnetic disorder at paramagnetic temperatures are investigated in single-site coherent potential approximation. It is shown that the nonmagnetic impurity shifts the band of carriers and suppresses the van Hove singularities of the local density of states (LDOS) depending on the value of impurity concentration. The magnetic impurity, however, broadens the band which depends on the strength of exchange coupling, and in the high impurity concentration, the van Hove singularities in the LDOS can completely disappear and the curves become smooth.