A New Quantum Phase Transition in the Coupled Quantum Dots System

TL;DR

This paper investigates a novel quantum phase transition in coupled quantum dots, revealing a new critical point with non-Fermi liquid behavior and analyzing conductance properties under various parameters.

Contribution

It introduces a new quantum critical fixed point in coupled quantum dots and characterizes its non-Fermi liquid behavior and conductance features.

Findings

Existence of a new quantum critical fixed point

Conductance peaks sharply at the critical point

Non-Fermi liquid behavior observed near the transition

Abstract

We study two quantum dots in the limit of strong dot-lead coupling and weak dot-dot tunneling. The model maps on Ising-coupled Kondo impurities. We argue that a new quantum critical fixed point exists at an intermediate value of the mutual capacitance, supporting non-Fermi liquid behaviour. We construct the total conductance across the double dot structure. It exhibits a strongly peaked behaviour as a function of the mutual capacitance, gate voltage, and temperature.