scholarly journals Tuning Valley Degeneracy with Band Inversion

2022 ◽  
Author(s):  
Michael Toriyama ◽  
Madison K. Brod ◽  
Lidia C Gomes ◽  
Ferdaushi A. Bipasha ◽  
B. Assaf ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Thermoelectric Performance ◽  
Band Inversion

Valley degeneracy is a key feature of the electronic structure that benefits the thermoelectric performance of a material. Despite recent studies which claim that high valley degeneracy can be achieved...

scholarly journals Tuning Valley Degeneracy with Band Inversion

2021 ◽  
Author(s):  
Michael Y. Toriyama ◽  
Madison K. Brod ◽  
Lidia C. Gomes ◽  
Ferdaushi A. Bipasha ◽  
Badih A. Assaf ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Rock Salt ◽  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Critical Degree ◽  
Band Inversion

Valley degeneracy is a key feature of the electronic structure that benefits the thermoelectric performance of a material. Despite recent studies which claim that high valley degeneracy can be achieved with inverted bands, our survey of rock-salt IV-VI compounds demonstrates that mere band inversion is an insufficient condition for high valley degeneracy; rather, there is a critical degree to which the bands must be inverted to induce multiple carrier pockets. The so-called “band inversion parameter” is a chemically-tunable parameter, offering a design route to achieving high valley degeneracy in compounds with inverted bands. We predict that the valley degeneracy of rock-salt IV-VI compounds can be increased from NV = 4 to NV = 24, which could result in a corresponding increase in the thermoelectric figure of merit zT.

Band inversion induced multiple electronic valleys for high thermoelectric performance of SnTe with strong lattice softening

Nano Energy ◽  
2020 ◽  
Vol 69 ◽  
pp. 104395 ◽  
Author(s):  
Guizhen Xie ◽  
Zhi Li ◽  
Tingting Luo ◽  
Hui Bai ◽  
Jinchang Sun ◽  
...  
Keyword(s):  
Thermoelectric Performance ◽  
Band Inversion ◽  
Lattice Softening

scholarly journals Molybdenum as a Versatile Dopant in SnTe: A Promising Material for Thermoelectric Application

2022 ◽  
Author(s):  
Sandhya U. Shenoy ◽  
Denthaje Krishna Bhat
Keyword(s):  
Electronic Structure ◽  
Fermi Level ◽  
Promising Material ◽  
Thermoelectric Performance ◽  
Thermoelectric Application

The key to enhance the thermoelectric performance of SnTe is to engineer its electronic structure by doping. It is essential that the beneficial features are exhibited at the Fermi level...

scholarly journals Electronic structure of the PrNiBi half-Heusler system based on the σGGA + U method

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
L. Mikaeilzadeh ◽  
A. Tavana ◽  
F. Khoeini
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Electronic Structure ◽  
Band Structure ◽  
Ground State ◽  
Density Functional ◽  
Functional Theory ◽  
Band Inversion ◽  
Topological State ◽  
Antiferromagnetic Ground State

AbstractIn this works, we study the electronic structure and magnetic properties of the Pr-Ni-Bi half-Heusler systems based on density functional theory. We use the σ GGA + U scheme to consider the effects of on-site electron-electron interactions. Results show that in contrast to the rough estimation of the total magnetic moment of the unit cell, based on the Slater-Pauling behavior in the half-Heusler systems, this system has an antiferromagnetic ground state because of the localized Pr-f electrons. By increasing the magnitude of the effective U parameter, band-inversion occurs in the band structure of this system, which shows the possibility of topological state occurrence.

Topological phonons and electronic structure of Li2BaSi class of semimetals

2021 ◽  
Author(s):  
Vineet Kumar Sharma ◽  
Birender Singh ◽  
Anan Bari Sarkar ◽  
Mayanak Kumar Gupta ◽  
Ranjan Mittal ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Transport Properties ◽  
Careful Analysis ◽  
Nodal Line ◽  
Theoretical Modelling ◽  
Spin Orbit Coupling ◽  
Band Inversion ◽  
Device Applications ◽  
Band Crossing ◽  
Nontrivial Topology

Abstract Extension of the topological concepts to the Bosonic systems has led to the prediction of topological phonons in materials. Here we discuss the topological phonons and electronic structure of Li2BaX (X = Si, Ge, Sn, and Pb) materials using first-principles theoretical modelling. A careful analysis of the phonon spectrum of Li2BaX reveals an optical mode inversion with the formation of nodal line states in the Brillouin zone. Our electronic structure results reveal a double band inversion at the Γ point with the formation of inner nodal-chain states in the absence of spin-orbit coupling (SOC). Inclusion of the SOC opens a materials-dependent gap at the band crossing points and transitions the system into a trivial insulator state. We also discuss the lattice thermal conductivity and transport properties of Li2BaX materials. Our results show that coexisting phonon and electron nontrivial topology with robust transport properties would make Li2BaX materials appealing for device applications.

Ternary CuSbSe2 chalcostibite: facile synthesis, electronic-structure and thermoelectric performance enhancement

2016 ◽  
Vol 4 (11) ◽  
pp. 4188-4193 ◽  
Author(s):  
Dan Zhang ◽  
Junyou Yang ◽  
Qinghui Jiang ◽  
Liangwei Fu ◽  
Ye Xiao ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Mechanical Alloying ◽  
Single Phase ◽  
Performance Enhancement ◽  
Phase Evolution ◽  
Thermoelectric Performance ◽  
Facile Synthesis ◽  
First Time

A single phase CuSbSe2 polycrystalline chalcostibite compound has been facilely synthesized through mechanical alloying for the first time, and the phase evolution has been revealed in detail.

Comparative studies of the electronic structure and thermoelectric properties in orthorhombic and tetragonal BaCu2Se2 by first-principles calculations

RSC Advances ◽  
2016 ◽  
Vol 6 (65) ◽  
pp. 60717-60722
Author(s):  
Daifeng Zou ◽  
Hairong Zheng ◽  
Jiangyu Li
Keyword(s):  
Electronic Structure ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Comparative Studies ◽  
Thermoelectric Performance ◽  
First Principles Calculations

Results show that the thermoelectric performance of tetragonal β-BaCu2Se2 is superior to orthorhombic α-BaCu2Se2.

Optimizing the thermoelectric performance of low-temperature SnSe compounds by electronic structure design

2015 ◽  
Vol 3 (25) ◽  
pp. 13365-13370 ◽  
Author(s):  
A. J. Hong ◽  
L. Li ◽  
H. X. Zhu ◽  
Z. B. Yan ◽  
J.-M. Liu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Low Temperature ◽  
Carrier Density ◽  
Figure Of Merit ◽  
Structure Design ◽  
Thermoelectric Performance ◽  
Merit Factor

Figure-of-merit factor ZT depending on hope-carrier density for single and polycrystal SnSe compounds at T = 675 K.

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