On the influence of tetrahedral covalent-hybridization on electronic band structure of topological insulators from first principles

Zhang, X. M.; Xu, Guizhou; Liu, E. K.; Liu, Z. Y.; Wang, W. H.; Wu, Guangheng

doi:10.1063/1.4906410

Cited by 3 publications

(3 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Moreover, we also perform the ELF maps project on the (1 1 0) plane of the LiCrS in types I, II, and III, respectively. The high- and low- ELF values in the graphs of ELF correspond to areas of localized electrons and the area around the maxima, respectively [ 35 ]. As shown in Figure 6 a,c, for the type I and type III arrangements, the regions of the highest ELF value are all around the main-group S atom along the S-Cr bound axes, indicating their sharing behavior and the occurrence of the covalent bond.…”

Section: Resultsmentioning

confidence: 99%

Largest Magnetic Moments in the Half-Heusler Alloys XCrZ (X = Li, K, Rb, Cs; Z = S, Se, Te): A First-Principles Study

2017

View full text Add to dashboard Cite

Abstract:A recent theoretical work indicates that intermetallic materials LiMnZ (Z = N, P) with a half-Heusler structure exhibit half-metallic (HM) behaviors at their strained lattice constants, and the magnetic moments of these alloys are expected to reach as high as 5 µ B per formula unit. (Damewood et al. Phys. Rev. B 2015, 91, 064409). This work inspired us to find new Heusler-based half-metals with the largest magnetic moment. With the help of the first-principles calculation, we reveal that XCrZ (X = K, Rb, Cs; Z = S, Se, Te) alloys show a robust, half-metallic nature with a large magnetic moment of 5 µ B at their equilibrium and strained lattice constants in their most stable phases, while the excellent HM nature of LiCrZ (Z = S, Se, Te) alloys can be observed in one of their metastable phases. Moreover, the effects of uniform strain in LiCrZ (Z = S, Se, Te) alloys in type II arrangement have also been discussed.

show abstract

Section: Resultsmentioning

confidence: 99%

Largest Magnetic Moments in the Half-Heusler Alloys XCrZ (X = Li, K, Rb, Cs; Z = S, Se, Te): A First-Principles Study

2017

View full text Add to dashboard Cite

show abstract

“…Several kinds of crystal structures are found or predicted to have a topological insulator phase: for example, Bi 2 Te 3 [1] and Bi 2 Se 3 [1] in the hexagonal structure; LaPtBi [10,11] half-Heusler compound [9,[12][13][14][15][16][17], oxide perovskite [18,19], halide perovskite [20][21][22], binary compound [23], Ba 2 BiIO 6 [24], and CaTePoO 6 [25] double perovskites in the cubic structure. The bulk bandgap for these Tls are in general smaller than 0.5 eV; for example, bismuth-based compounds such as Bi 2 Te 3 [26] are 0.17 eV, Bi 2 Te 2 S [27] 0.3 eV, and PbBi 4 Te 4 S 3 is 0.2 eV in the experiment and 0.3 eV in theory.…”

Section: Introductionmentioning

confidence: 99%

Large Bandgap Topological Insulator in Oxide APoO3 (A = Be, Mg, Ca, Sr, Ba, and Ra) Perovskite: An Ab Initio Study

Lee

Tung

2021

Applied Sciences

View full text Add to dashboard Cite

Under the density functional theory framework, we have calculated the electronic and elastic properties of APoO3 (A = Be, Mg, Ca, Sr, Ba, and Ra) cubic perovskites. We found that CaPoO3, SrPoO3, BaPoO3, and RaPoO3 are topological insulators (TIs) with very large bandgaps of 0.861, 0.871, 0.820, and 0.810 eV, respectively. The nontrivial band topology together with the Z2 topological number of APoO3 perovskite are investigated. We also theoretically determine the three independent elastic constants C11, C12, and C44 of the APoO3 perovskite. The bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, and anisotropy factor are also calculated from the obtained elastic constants. We found that the Debye temperature for the APoO3 perovskite is around 330-370 K. In the bulk APoO3 perovskite, if the center Po atom is shifted 0.09Å away from the center, the induced electric polarization is quite large, being around 0.02 C/m2. In the surface band calculation, we found that both AO and PoO2 surfaces give rise to contributions to the conduction channel. If the Po atom moves both in-plane and out-of-plane, we show that both electric polarization and topologically protect surface conduction states exist in APoO3 perovskite, indicating that these oxide APoO3 perovskites are ferroelectric TIs and might be useful for spintronic applications.

show abstract

“…由于第一原理计算已证实此结构体系拓扑Z 2 不变量没有反对称性的量子本质, 加上这个系列材料如磁性和超导性等其他有趣的物理性质, 于是基于密度泛函理论的第一性原理计算方法将三元半Heusler化合物转变为三维拓扑绝缘体成为研究热点 [9,10] . 对于三维拓扑绝缘体半Heusler化合物的研究, 结合这些材料的磁性和超导性质, 在实验方面也成为了一个有巨大价值的研究平台 [11,12] . 目前通过第一原理计算, 大量的半Heusler三元化合物已经被发现具有反带结构, 例如LuPtSb, ScPtBi, YPdBi, ThPtPb, 都可以通过单轴应力成为三维拓扑绝缘体的备选材料 [13] .…”

unclassified

Band structure of topological insulator Li(Na)AuS

许佳玲¹,

贾利云²,

Liu³

et al. 2021

Acta Phys. Sin.

View full text Add to dashboard Cite

Half-Heusler semiconductors exhibit similar properties: the differences among their properties lie only in the fact that in ternary compositions the zinc-blende binary substructure does not provide the required 18 electrons, but this is improved by adding an extra transition metal, which restores the electronic balance. Half-Heusler ternary compound with 18 valence electrons under an appropriate uniaxial strain is a topological insulating phase. Most importantly, it is proposed that in the half-Heusler family, the topological insulator should allow the incorporating of superconductivity and magnetism. Using the first-principle full-potential linearized augmented wave method we study the band structure of a series of Li(Na)AuS topological insulators. The electronic and magnetic properties of Heusler alloys are investigated by the WIEN2k package. The exchange-correlations are treated within the generalized gradient approximation of PerdeweBurke and Ernzerhof (GGA), the local spin density approximation (LSDA), by using the modified Becke-Johnson exchange potential and the correlation potential of the local-density approximation (MBJ). Spin-orbit coupling is treated by means of the second variational procedure with the scalar-relativistic calculation as basis. We first determine the equilibrium lattice constants by calculating the total energy. The theoretical lattice constant of LiAuS full-potential GGA is 6.02 Å, which is somewhat greater than the result of pseudopotential(5.99 Å). The calculated equilibrium lattice parameter is 5.86 Å for LSDA. Most of the half-Heusler compounds have band inversion, and open the nature band gaps, but the gap of MBJ is not very good. Smaller uniaxial stress damages the cubic structure and also such a natural band gap of topological insulators. By applying uniaxial tensile stress until the equilibrium position is reached in all directions of the structure, the system band gap value is about 0.2 eV, which is consistent with the result obtained from the band gap of cubic structure equilibrium position. When uniaxial tensile stress is 41%, the system turns into a tetragonal structure, the equilibrium lattice constant is a = 5.2477 Å and c/a = 1.41. We use the method of substitution of homologous elements to ensure the properties of topological insulator of materials without changing the cubic structure, and open the bandgap of materials under the equilibrium lattice constant of the system, thereby improving the feasibility of experimental synthesis of topological insulator materials. Our results for the doping suggest that epitaxial strain encountered during experiment can result in electronic topological transition. We hope that the results presented here conduce to further experimental investigation of the electronic topological transition in half-Heusler compounds.

show abstract

On the influence of tetrahedral covalent-hybridization on electronic band structure of topological insulators from first principles

Cited by 3 publications

References 44 publications

Largest Magnetic Moments in the Half-Heusler Alloys XCrZ (X = Li, K, Rb, Cs; Z = S, Se, Te): A First-Principles Study

Largest Magnetic Moments in the Half-Heusler Alloys XCrZ (X = Li, K, Rb, Cs; Z = S, Se, Te): A First-Principles Study

Large Bandgap Topological Insulator in Oxide APoO3 (A = Be, Mg, Ca, Sr, Ba, and Ra) Perovskite: An Ab Initio Study

Band structure of topological insulator Li(Na)AuS

Contact Info

Product

Resources

About