Kondo effect in the helical edge liquid of the quantum spin Hall state

Abstract

Following the recent observation of the quantum spin Hall (QSH) effect in HgTe quantum wells, an important issue is to understand the effect of impurities on transport in the QSH regime. Using linear response and renormalization group methods, we calculate the edge conductance of a QSH insulator as a function of temperature in the presence of a magnetic impurity. At high temperatures, Kondo and/or two-particle scattering give rise to a logarithmic temperature dependence. At low temperatures, for weak Coulomb interactions in the edge liquid the conductance is restored to unitarity with unusual power-laws characteristic of a `local helical liquid', while for strong interactions transport proceeds by weak tunneling through the impurity where only half an electron charge is transferred in each tunneling event.

5 pages, 2 figures; version accepted for publication in Phys. Rev. Lett

References in corpus (6)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Field Theory of Time-Reversal Invariant Insulators
• The Quantum Spin Hall Effect: Theory and Experiment
• Quantum Spin Hall Effect in Inverted Type II Semiconductors
• The Helical Liquid and the Edge of Quantum Spin Hall Systems

Cited by in corpus (4)

• Conductance of a helical edge liquid coupled to a magnetic impurity
• Full electrical control of Charge and Spin conductance through Interferometry of Edge States in Topological Insulators
• Spin polarised scanning tunneling probe for helical Luttinger liquids
• Coulomb drag between helical edge states