Phase transitions in two tunnel-coupled HgTe quantum wells: Bilayer graphene analogy and beyond.

ABSTRACT: HgTe quantum wells possess remarkable physical properties as for instance the quantum spin Hall state and the "single-valley" analog of graphene, depending on their layer thicknesses and barrier composition. However, double HgTe quantum wells yet contain more fascinating and still unrevealed features. Here we report on the study of the quantum phase transitions in tunnel-coupled HgTe layers separated by CdTe barrier. We demonstrate that this system has a 3/2 pseudo spin degree of freedom, which features a number of particular properties associated with the spin-dependent coupling between HgTe layers. We discover a specific metal phase arising in a wide range of HgTe and CdTe layer thicknesses, in which a gapless bulk and a pair of helical edge states coexist. This phase holds some properti

SUBMITTER: Krishtopenko SS 

PROVIDER: S-EPMC4967852 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature