Strain-induced topological insulator phase transition in HgSe

Winterfeld, Lars; Agapito, Luis A.; Jin, Li; Kioussis, Nicholas; Blaha, Peter; Chen, Yong P.

doi:10.1103/physrevb.87.075143

Cited by 41 publications

(46 citation statements)

References 39 publications

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“…Atomic positions are relaxed using the Perdew-Burke-Ernzerhof functional [15]. For noncentrosymmetric systems, the Z 2 can be determined either by integrating both the Berry's connection and curvature over half of the BZ [16], or equivalently, by calculating the evolution of the Wannier function center (WFC) in reciprocal space during a ''time-reversal pumping'' process [10,17,18]. This corresponds to the phase factor of the eigenvalues of the position operatorX projected into the occupied subspace.…”

Section: H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

Novel Family of Chiral-Based Topological Insulators: Elemental Tellurium under Strain

et al. 2013

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Employing ab initio electronic structure calculations, we predict that trigonal tellurium consisting of weakly interacting helical chains undergoes a trivial insulator to strong topological insulator (metal) transition under shear (hydrostatic or uniaxial) strain. The transition is demonstrated by examining the strain evolution of the band structure, the topological Z 2 invariant and the concomitant band inversion. The underlying mechanism is the depopulation of the lone-pair orbitals associated with the valence band via proper strain engineering. Thus, Te becomes the prototype of a novel family of chiral-based three-dimensional topological insulators with important implications in spintronics, magneto-optics, and thermoelectrics. DOI: 10.1103/PhysRevLett.110.176401 PACS numbers: 71.15.Ap, 72.25.Dc, 73.20.At, 73.43.Nq The recent discovery of three-dimensional (3D) topological insulators (TIs) has sparked intense efforts in the search for novel materials that exhibit this new quantum-mechanical state of matter driven by strong spin-orbit coupling, which leads to the appearance of spin-momentum-locked topologically protected surface states with a Dirac-cone energy dispersion [1][2][3]. Ongoing research efforts focus primarily on the prototypical family of Bi 2 Te 3 , Bi 2 Se 3 , and Sb 2 Te 3 3D TIs, which exhibit a quintuple layered structure along the c axis of the hexagonal lattice. The intra-and interlayer coupling within one quintuple layer is covalentlike while the interaction between two quintuple layers is much weaker, predominantly of the van der Waals type [3][4][5].The heavier group-VI elements selenium and tellurium are ubiquitous in most of the recently discovered binary or ternary TIs and exhibit a wide variety of interesting properties under pressure. They undergo complex structural changes [6], exhibit semiconductor-to-metal transitions [7], have unusual melting curves [8], and some of their high-pressure phases are superconducting at low temperatures [6]. At ambient conditions, tellurium has a trigonal crystal structure (Te-I) with space group D 4 3 consisting of weakly interacting infinite helical chains arranged in a hexagonal array, which spiral around axes parallel to c. The unit cell shown in Fig. 1(a) has three atoms at the positions (u, 0, 0), (0, u, 1=3), and ( " u, " u, 2=3) in units of the lattice vectors [9], where u is the internal atomic position parameter. Each atom forms strong covalentlike intrachain bonds with its two nearest neighbors (NNs) and weak van der Waals-like interchain bonds with its four next NNs, with bond lengths of r ¼ 2:91 # A and R ¼ 3:43 # A, respectively. This unique feature is reflected in liquid-state studies of Te which showed that the chain structure is retained above the melting temperature [8].In this Letter we predict that Te-I, a noncentrosymmetric material, becomes a strong TI or topological metal (TM) under application of shear or uniform and uniaxial strain, respectively. In most reported TIs to date, the band inversion and the gap closing occur n...

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Section: H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

Novel Family of Chiral-Based Topological Insulators: Elemental Tellurium under Strain

et al. 2013

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“…15 Another approach is to use external electric field, which could lead to transition of a normal insulator (NI) to a TI. 35 Group V elemental monolayers, such as black and blue phosphorene 36,37 , arsenene 38,39 and antimonene, 38 are drawing intensive interest because of their novel physicochemical properties. 32 Strain modification is also a favorable strategy for switching NIs into TIs.…”

Section: Introductionmentioning

confidence: 99%

Quantum spin hall insulators in strain-modified arsenene

2015

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By means of density functional theory (DFT) computations, we predict that the suitable strain modulation of honeycomb arsenene results in a unique two-dimensional (2D) topological insulator (TI) with a sizable bulk gap (up to 696 meV), which could be characterized and utilized at room temperature. Without considering any spin-orbit coupling, the band inversion occurs around the Gamma (G) point at tensile strains larger than 11.7%, which indicates the quantum spin Hall effect in arsenene at appropriate strains. The nontrivial topological phase was further confirmed by the topological invariant ν = 1 and edge states with a single Dirac-type crossing at the G point. Our results provide a promising strategy for designing 2D TIs with large bulk gaps from commonly used materials.

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“…2 Various attempts subsequently have been directed to the investigation of straininduced topological phase transitions. [14][15][16][17][18][19][20][21][22] Specifically, the properties at the transition point between the topological and trivial phases, such as sharp Raman anomalies 23 and Weyl semimetallic phases with broken symmetry, 24,25 have attracted attention, because the phase transitions are essential for understanding the underlying physics.…”

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Series of topological phase transitions in TiTe2under strain

2013

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First-principles calculations are performed to investigate the topological properties of TiTe 2 under hydrostatic pressure, uniaxial strain, and biaxial strain. It is found that the system is unusually accessible to strain effects and the first compound that under hydrostatic pressure (up to experimentally reasonable 30 GPa) is subject to a series of four topological phase transitions, which are related to band inversions at different points of the Brillouin zone. Therefore, TiTe 2 enables experimental access to all these transitions in a single compound. As a new kind of quantum matter, topological insulators (TIs) have been intensively studied during the last decade. [1][2][3][4] They are characterized by a band gap in the bulk and an odd number of gapless edge/surface states. The surface states originate from spin-orbit coupling and are topologically protected by time-reversal symmetry, which makes TIs promising materials for spintronics and quantum computation applications. Many three-dimensional (3D) TIs have been theoretically predicted and experimentally confirmed. [5][6][7][8][9][10][11][12][13] However, the search for TIs that are more suitable for experimental investigations and applications is still a key issue. In this context, strain engineering has proven to be a fruitful path, as HgTe had been predicted to be a strong TI under strain.2 Various attempts subsequently have been directed to the investigation of straininduced topological phase transitions.14-22 Specifically, the properties at the transition point between the topological and trivial phases, such as sharp Raman anomalies 23 and Weyl semimetallic phases with broken symmetry, 24,25 have attracted attention, because the phase transitions are essential for understanding the underlying physics.Based on density functional theory, several methods have been introduced for discovering 3D TIs, 8 particularly the investigation of the surface electronic structure, the adiabatic continuity band transformation, the band inversion picture, and the direct calculation of the Z 2 topological invariants. The latter have been introduced by Kane and Mele to characterize time-reversal symmetry protected systems.1 Values of Z 2 = 0 and 1 represent topologically trivial and nontrivial phases, respectively. In a 3D system, the four Z 2 topological invariants (ν 0 ; ν 1 ν 2 ν 3 ) are used for classification. A nonzero ν 0 indicates that the system is a strong TI, whereas when ν 0 = 0 the system has to be further classified according to ν 1 , ν 2 , and ν 3 . Systems with ν 1/2/3 = 0 are called weak TIs, while (0;000) is a normal insulator. A strong TI cannot be directly connected to a weak TI or a normal insulator by any adiabatically continuous transformation of the band structure.TiTe 2 is isostructural to the compound 1T-TiSe 2 , which has been investigated for decades because of its charge density wave. 26,27 Under pressure 1T-TiSe 2 transforms from a charge density wave into a superconducting phase at low temperature, 28 indicating that further interesting ef...

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Strain-induced topological insulator phase transition in HgSe

Cited by 41 publications

References 39 publications

Novel Family of Chiral-Based Topological Insulators: Elemental Tellurium under Strain

Novel Family of Chiral-Based Topological Insulators: Elemental Tellurium under Strain

Quantum spin hall insulators in strain-modified arsenene

Series of topological phase transitions in TiTe2under strain

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