Phase transitions in two tunnel-coupled HgTe quantum wells. Bilayer graphene analogy and beyond
arXiv:1604.02423 · doi:10.1038/srep30755
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 properties of bilayer graphene such as an unconventional quantum Hall effect and an electrically-tunable band gap. In this 'bilayer graphene' phase, electric field opens the band gap and drives the system into the quantum spin Hall state. Furthermore, we discover a new type of quantum phase transition arising from a mutual inversion between second electron- and hole-like subbands. This work paves the way towards novel materials based on multi-layered topological insulators.
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Cited by in corpus (26)
- Temperature-induced topological phase transition in HgTe quantum wells
- Temperature-driven single-valley Dirac fermions in HgTe quantum wells
- Large gap quantum spin Hall insulator, massless Dirac fermions and bilayer graphene analogue in InAs/Ga(In)Sb heterostructures
- Kramers pairs of Majorana corner states in a topological insulator bilayer
- Realistic picture of helical edge states in HgTe quantum wells
- Massless Dirac fermions in III-V semiconductor quantum wells
- Perspectives of HgTe Topological Insulators for Quantum Hall Metrology
- Two-dimensional topological insulator state in double HgTe quantum well
- Landau level spectroscopy of valence bands in HgTe quantum wells: Effects of symmetry lowering
- Unconventional Reentrant Quantum Hall Effect in a HgTe/CdHgTe Double Quantum Well
- Disorder-induced phase transition in Dirac systems beyond the linear approximation
- Engineering topological phases in triple HgTe/CdTe quantum wells
- Many-particle effects in optical transitions from zero-mode Landau levels in HgTe quantum wells
- Multiple crossing of Landau levels of two-dimensional fermions in double HgTe quantum wells
- Asymmetric versus symmetric double quantum wells: Band gap tuning without electric field
- Disorder-induced phase transitions in double HgTe quantum wells
- Characterization of helical states in semiconductor quantum wells using quantum information quantities
- Quasiparticle picture of topological phase transitions induced by interactions
- Hard wall edge confinement in 2D topological insulators and the energy of the Dirac Point
- Tunable Competing Electronic Orders in Double Quantum Spin Hall Superlattices
- Engineering Majorana Kramers Pairs In Synthetic High Spin Chern Insulators
- Many-particle hybridization of optical transitions from zero-mode Landau levels in HgTe quantum wells
- Self-Consistent Model for Gate Control of Narrow-, Broken-, and Inverted-Gap (Topological) Heterostructures
- Interband plasmons due to Mexican hat dispersion in two-dimensional materials with inverted bands
- Relativistic collapse of Landau levels of Kane fermions in crossed electric and magnetic fields
- Higher-order topological insulator in cubic semiconductor quantum wells