Transport properties for a quantum dot coupled to normal leads with pseudogap

TL;DR

This paper investigates how a pseudogap in the leads' density of states affects transport in a quantum dot, revealing significant changes in conductance at a critical exponent value.

Contribution

It provides a detailed analysis of transport properties in a quantum dot with pseudogap leads using second-order perturbation theory, highlighting the impact of the pseudogap exponent on conductance features.

Findings

Cusp or dip structures in the density of states induced by the pseudogap

Significant changes in current-voltage characteristics at r=1/2

Altered differential conductance behavior due to pseudogap effects

Abstract

We study transport properties for a quantum dot coupled to normal leads with a pseudogap density of states at zero temperature, using the second-order perturbation theory based on the Keldysh formalism. We clarify that the hybridization function $\Gamma(\omega)\propto |\omega|^r\; (0 \le r < 1) $ induces the cusp or dip structure in the density of states in the dot when finite bias voltage is applied to the interacting quantum dot system. It is found that the current-voltage characteristics and differential conductance are drastically changed at $r=1/2$.