Roles of Potential Gradient and Electrode Bandwidth on Negative Differential Resistance in One-Dimensional Band Insulator

TL;DR

This paper investigates how potential gradients and electrode bandwidth influence negative differential resistance in one-dimensional band insulators, revealing that both factors can induce NDR through band tilting and finite bandwidth effects.

Contribution

It systematically analyzes the roles of potential distribution and electrode bandwidth in causing NDR, highlighting mechanisms in uncorrelated systems.

Findings

NDR is caused by potential gradient and finite electrode bandwidth.

Potential gradient tilts the energy band, reducing effective bandwidth.

NDR occurs even with large electrode bandwidth due to band tilting.

Abstract

A negative differential resistance (NDR) in a one-dimensional band insulator attached to electrodes is investigated. We systematically examine the effects of an electrode bandwidth and a potential distribution inside the insulator on current-voltage characteristics. We show that, in uncorrelated systems, the NDR is generally caused by a linear potential gradient as well as by a finite electrode bandwidth. In particular, the former reduces the effective bandwidth of the insulator for elastic tunneling by tilting its energy band, so that it brings about the NDR even in the limit of large electrode bandwidth.