Comparison of inelastic and quasi-elastic scattering effects on nonlinear electron transport in quantum wires

TL;DR

This paper investigates how inelastic and quasi-elastic scattering influence nonlinear electron transport in quantum wires, revealing distinct effects on electron mobility and distribution functions under varying impurity and phonon scattering conditions.

Contribution

It provides an accurate solution to the Boltzmann equation considering both scattering types, highlighting their different impacts on electron distribution and mobility in quantum wires.

Findings

Non-differential mobility shifts from linear to parabolic temperature dependence.

Maximum in differential mobility as a function of dc field.

Distinct distribution function behaviors for inelastic versus quasi-elastic scattering.

Abstract

When impurity and phonon scattering coexist, the Boltzmann equation has been solved accurately for nonlinear electron transport in a quantum wire. Based on the calculated non-equilibrium distribution of electrons in momentum space, the scattering effects on both the non-differential (for a fixed dc field) and differential (for a fixed temperature) mobilities of electrons as functions of temperature and dc field were demonstrated. The non-differential mobility of electrons is switched from a linearly increasing function of temperature to a parabolic-like temperature dependence as the quantum wire is tuned from an impurity-dominated system to a phonon-dominated one [see T. Fang, {\em et al.}, \prb {\bf 78}, 205403 (2008)]. In addition, a maximum has been obtained in the dc-field dependence of the differential mobility of electrons. The low-field differential mobility is dominated by the impurity scattering, whereas the high-field differential mobility is limited by the phonon scattering [see M. Hauser, {\em et al.}, Semicond. Sci. Technol. {\bf 9}, 951 (1994)]. Once a quantum wire is dominated by quasi-elastic scattering, the peak of the momentum-space distribution function becomes sharpened and both tails of the equilibrium electron distribution centered at the Fermi edges are raised by the dc field after a redistribution of the electrons is fulfilled in a symmetric way in the low-field regime. If a quantum wire is dominated by inelastic scattering, on the other hand, the peak of the momentum-space distribution function is unchanged while both shoulders centered at the Fermi edges shift leftward correspondingly with increasing dc field through an asymmetric redistribution of the electrons even in low-field regime [see C. Wirner, {\em et al.}, \prl {\bf 70}, 2609 (1993)].