Quantum phase transition and emergent symmetry in a quadruple quantum dot system.

Journal Article (Journal Article)

We propose a system of four quantum dots designed to study the competition between three types of interactions: Heisenberg, Kondo, and Ising. We find a rich phase diagram containing two sharp features: a quantum phase transition (QPT) between charge-ordered and charge-liquid phases and a dramatic resonance in the charge liquid visible in the conductance. The QPT is of the Kosterlitz-Thouless type with a discontinuous jump in the conductance at the transition. We connect the resonance phenomenon with the degeneracy of three levels in the isolated quadruple dot and argue that this leads to a Kondo-like emergent symmetry from left-right Z2 to U(1).

Full Text

Duke Authors

Cited Authors

  • Liu, DE; Chandrasekharan, S; Baranger, HU

Published Date

  • December 13, 2010

Published In

Volume / Issue

  • 105 / 25

Start / End Page

  • 256801 -

PubMed ID

  • 21231607

Electronic International Standard Serial Number (EISSN)

  • 1079-7114

International Standard Serial Number (ISSN)

  • 0031-9007

Digital Object Identifier (DOI)

  • 10.1103/physrevlett.105.256801


  • eng