Effects of a transversely polarized electric field on the quantum transport in narrow channels

TL;DR

This study investigates how a transversely polarized, time-dependent electric field influences quantum transport in narrow channels, revealing conductance suppression, resonance structures, and the importance of non-perturbative effects due to singular density of states.

Contribution

It demonstrates the impact of a transversely polarized, time-dependent electric field on quantum transport, highlighting the role of quasi-bound states and the necessity of beyond-perturbation analysis.

Findings

Suppression of dc conductance G with increasing chemical potential

Resonance structures related to quasi-bound states and multi-photon processes

Singular density of states at subband bottoms influences electron-field interactions

Abstract

The quantum transport in a narrow channel (NC) is studied in the presence of a time-dependent delta-profile electric field. The electric field is taken to be transversely polarized, with frequency $\omega$, causing inter-subband and inter-sideband transitions. Suppression in the dc conductance $G$ is found, which escalates with the chemical potential. There are structures in $G$ which are related to the quasi-bound states (QBS) features. Major dip, and dip-and-peak, structures occur when an incident electron makes transition to a subband edge by absorbing or emitting one, and two, $\hbar\omega$, respectively. Structures associated with three $\hbar\omega$ processes are recognized. The QBS are closely associated with the singular density of states (DOS) at subband bottoms. Our results indicate that, due to this singular features of the DOS, the interaction of the electron with the electric field has to be treated beyond finite order perturbation.