Local ferroelectricity in thermoelectric SnTe above room temperature driven by competing phonon instabilities and soft resonant bonding

Aggarwal, Leena; Banik, Ananya; Anand, Shashwat; Waghmare, Umesh V.; Biswas, Kanishka; Sheet, Goutam

doi:10.1016/j.jmat.2016.04.001

Cited by 29 publications

(23 citation statements)

References 33 publications

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“…7 is predicted [3] at the Z point of the BZ in noncentrosymmetric r-SnTe which has been attributed to the Rashba splitting of the bulk bands, raising questions about the origin of our ARPES observations. Although a noncentrosymmetric, ferroelectric r-SnTe is expected to be stable only below 100 K [40], several works report ferroelectricity in SnTe at room temperature [41] and others provide evidence [42] for rhombohedral distortions persisting up to room temperature in a cubic matrix. Therefore, at first sight a Rashba spitting due to noncentrosymmetric r-SnTe cannot be excluded as a possible explanation of our ARPES observations.…”

Section: Discussionmentioning

confidence: 99%

Topological band crossings in epitaxial strained SnTe

Fragkos

Sant

Alvarez

et al. 2019

Phys. Rev. Materials

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Epitaxial SnTe (111) is grown by molecular-beam epitaxy on Bi 2 Te 3 substrates. Structural evaluation indicates that SnTe deviates from cubic due to in-plane compressive strain, which induces significant changes in the electronic band structure. More specifically, a pair of gapless crossings between the two uppermost valence bands occurs in k space along the out-of-plane Z direction of the Brillouin zone, associated with a band inversion, thus defining topological three-dimensional Dirac nodes. Combined first-principles calculations and angle-resolved photoelectron spectroscopy reveal an overtilted Dirac cone indicating that the crossing is a topological type-III Dirac node at the borders between type-I and type-II Dirac nodes.

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Section: Discussionmentioning

confidence: 99%

Topological band crossings in epitaxial strained SnTe

Fragkos

Sant

Alvarez

et al. 2019

Phys. Rev. Materials

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“…This phenomenon leads to substantial anharmonicity of the lattice dynamics, contributing to the observed ultralow thermal conductivity important for thermoelectrics, 49 and has been a topic of intense interest since the first reports. 50 – 57 Our recent work has shown a similar dynamic displacement of Sn 2+ in CsSnBr 3 at ambient and elevated temperatures, 29 suggesting that an emphanitic local distortion of the metal halide network may also be present in the technologically important hybrid halide perovskites.…”

Section: Introductionmentioning

confidence: 89%

Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites

et al. 2017

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“…In the other side ferroelectricity has been observed above room temperature in rock salt SnTe recently. [ 55,56 ] From Figure 3 we note that the Weyl scenario will be present with larger FE displacements as compared with the Jahn–Teller distortion, enlarging also the energy splitting between the Weyl nodes, making it probable to be verified experimentally.…”

Section: Figurementioning

confidence: 97%

Dirac and Weyl Semimetals in Sn_1−xIn_xTe

Schmidt

Srivastava

2020

Physica Rapid Research Ltrs

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The recent realization of Weyl fermions in materials [1-10] has received a great deal of attention due to their connection with particle physics, in addition to the promise for technological applications. [11-13] These fermions belong to the topological semimetal class of materials, with accidental degeneracy states around the Fermi level that are protected by topology and symmetry. The protected Weyl fermions present a nonvanishing Chern number around each chiral node. The degenerated chiral points are located in the bulk band structure, connected with surface Fermi arcs. [3-9] There are some conditions to realize Weyl semimetal (WSM) in an inverted bandgap 3D material: the valence and conduction bands must touch each other at the some point of the bulk Brillouin zone (BZ), and a lack of either time reversal or inversion symmetry must occur. With that, the crossing point is symmetry-preserved and pairs of Weyl nodes with opposite chirality are realized. If time reversal and inversion symmetry are preserved in an inverted gap system, the Weyl nodes annihilate, resulting in a Dirac semimetal (DSM) phase. [14-21] In this case the net Chern number is zero; the Dirac crossing is fourfold degenerated and it is not topologically protected, [10] but crystal symmetry can protect the degeneracies if the semimetal character comes from a topological insulator bulk gap closure. Recently, it has been predicted that distinct semimetal topological phases can be obtained by defect engineering with impurities [22] in topological crystalline insulator (TCI) materials. This novel topological class has attracted attention lately [23-29] because their topological sates are protected by crystal symmetry, distinct from Z 2 topological insulators that are protected by time reversal symmetry. Pressure also has been shown to induce topological semimetal phase in TCIs. [30]

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Local ferroelectricity in thermoelectric SnTe above room temperature driven by competing phonon instabilities and soft resonant bonding

Cited by 29 publications

References 33 publications

Topological band crossings in epitaxial strained SnTe

Topological band crossings in epitaxial strained SnTe

Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites

Dirac and Weyl Semimetals in Sn_1−xIn_xTe

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Local ferroelectricity in thermoelectric SnTe above room temperature driven by competing phonon instabilities and soft resonant bonding

Cited by 29 publications

References 33 publications

Topological band crossings in epitaxial strained SnTe

Topological band crossings in epitaxial strained SnTe

Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites

Dirac and Weyl Semimetals in Sn1−xInxTe

Contact Info

Product

Resources

About

Dirac and Weyl Semimetals in Sn_1−xIn_xTe