Electrically tunable two-channel Kondo fixed points in helical liquids

Yu Li Lee, Yu Wen Lee

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


We study a quantum dot coupled to two edge states of a quantum spin Hall insulator through electron tunnelings in the presence of a Rashba spin-orbital interaction induced by an external electric field. We show that if the electron interactions on the edge states are repulsive, there are two possible phases, depending on the Luttinger liquid parameter K. For 1/2<K<1, the low-temperature physics is controlled by a previously identified two-channel Kondo fixed point. For the edge states with even stronger repulsive interactions, i.e., 1/4<K<1/2, the system reaches another phase at low temperatures, described by a new two-channel Kondo fixed point. This phase is separated from the original one by a continuous phase transition upon varying the value of K through the external electric field. The corresponding critical point is described by a free Dirac fermion backscattered by a local potential. We investigate the low-temperature properties associated with this new fixed point and also discuss the scaling behaviors of the system at the critical point.

Original languageEnglish
Article number035112
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number3
Publication statusPublished - 2013 Jul 9

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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