Orbital chemistry of high valence band convergence and low-dimensional topology in PbTe

2021 ◽  
Author(s):  
Madison K. Brod ◽  
G. Jeffrey Snyder
Keyword(s):  
Valence Band ◽  
Tight Binding ◽  
Thermoelectric Performance ◽  
Orbital Interactions ◽  
Low Dimensional Topology ◽  
Tight Binding Method ◽  
Low Dimensional ◽  
Insight Into ◽  
High Valence Band

The tight-binding method provides insight into the orbital interactions that lead to the exceptional thermoelectric performance of PbTe. Using this framework, we can predict strategies to achieve enhanced thermoelectric performance in new alloys.

Efficient Photoluminescence from Thin Films of Polypyrrole

2010 ◽  
Vol 663-665 ◽  
pp. 300-303 ◽  
Author(s):  
Yuan Ming Huang ◽  
Bao Gai Zhai ◽  
Qing Lan Ma
Keyword(s):  
Thin Films ◽  
Valence Band ◽  
Electronic Structures ◽  
Conjugated Polymer ◽  
Tight Binding ◽  
Electronic Transitions ◽  
Visible Absorption ◽  
Ultraviolet Excitation ◽  
Tight Binding Method ◽  
Visible Absorption Spectroscopy

A soluble polypyrrole without any substituent groups was obtained by controlling the oxidation level of polypyrrole in the presence of oxygen. Upon the exposure to the 325 nm ultraviolet excitation from a helium-cadmium laser, thin films of the non-substituted polypyrrole could give off strong photoluminescence with its peak at about 530 nm. To elucidate the origin of the recorded strong photoluminescence, we measured the absorption spectra of the polypyrrole thin films with ultraviolet-visible absorption spectroscopy and our data indicated the appropriately oxidized polypyrrole are free of polarons. With the help of the electronic structures calculated with Hückel tight-binding method, the intense photoluminescence is interpreted in terms of the direct electronic transitions from the conduction band to valence band of the conjugated polymer.

Antimony as A Passivant of Si(111) in the Si(111) (√3×√3)-Sb System

1992 ◽  
Vol 259 ◽  
Author(s):  
A. Hughes ◽  
T-H. Shen ◽  
C.C. Matthai
Keyword(s):  
Fermi Level ◽  
Valence Band ◽  
Density Of States ◽  
Surface State ◽  
Tight Binding ◽  
Valence Band Maximum ◽  
Electronic Density ◽  
Band Maximum ◽  
Electronic Density Of States ◽  
Tight Binding Method

ABSTRACTThe electronic density of states (DOS) for the Si(111) (√3×√3)-Sb system has been calculated using the tight binding method in the Extended Hiickel Approximation. We find that there is a gap of about 0.8eV between the valence band maximum (VBM) and a surface state. This is in contrast with the case of the unreconstructed (lxl) surface where the Fermi level lies at the surface state.

Calculation of the valence band of NaF by the tight binding method

1969 ◽  
Vol 29 (11) ◽  
pp. 656-657 ◽  
Author(s):  
C. Gout ◽  
R. Frandon ◽  
J. Sadaca
Keyword(s):  
Valence Band ◽  
Tight Binding ◽  
Tight Binding Method

Geometry and Physics: Volume II

2018 ◽  
Keyword(s):  
Moduli Spaces ◽  
Mirror Symmetry ◽  
Geometric Analysis ◽  
Mathematical Physics ◽  
Poisson Geometry ◽  
Special Holonomy ◽  
Low Dimensional Topology ◽  
Generalized Complex Structures ◽  
Wide Range ◽  
Low Dimensional

These volumes contain the proceedings of the conference held at Aarhus, Oxford and Madrid in September 2016 to mark the seventieth birthday of Nigel Hitchin, one of the world’s foremost geometers and Savilian Professor of Geometry at Oxford. The proceedings contain twenty-nine articles, including three by Fields medallists (Donaldson, Mori and Yau). The articles cover a wide range of topics in geometry and mathematical physics, including the following: Riemannian geometry, geometric analysis, special holonomy, integrable systems, dynamical systems, generalized complex structures, symplectic and Poisson geometry, low-dimensional topology, algebraic geometry, moduli spaces, Higgs bundles, geometric Langlands programme, mirror symmetry and string theory. These volumes will be of interest to researchers and graduate students both in geometry and mathematical physics.

Insight into the transport properties and enhanced thermoelectric performance of n-type Pb1−xSbxTe

2021 ◽  
Vol 860 ◽  
pp. 158355
Author(s):  
Taras Parashchuk ◽  
Ihor Horichok ◽  
Artur Kosonowski ◽  
Oleksandr Cherniushok ◽  
Piotr Wyzga ◽  
...  
Keyword(s):  
Transport Properties ◽  
Thermoelectric Performance ◽  
Insight Into

scholarly journals Ab Initio Study of Ferroelectric Critical Size of SnTe Low-Dimensional Nanostructures

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 732 ◽  
Author(s):  
Takahiro Shimada ◽  
Koichiro Minaguro ◽  
Tao Xu ◽  
Jie Wang ◽  
Takayuki Kitamura
Keyword(s):  
Density Functional ◽  
Critical Size ◽  
Density Functional Theory Calculations ◽  
Cell Width ◽  
Functional Theory ◽  
Unit Cells ◽  
Principle Density Functional Theory ◽  
Low Dimensional ◽  
Insight Into ◽  
Ferroelectric Perovskite

Beyond a ferroelectric critical thickness of several nanometers existed in conventional ferroelectric perovskite oxides, ferroelectricity in ultimately thin dimensions was recently discovered in SnTe monolayers. This discovery suggests the possibility that SnTe can sustain ferroelectricity during further low-dimensional miniaturization. Here, we investigate a ferroelectric critical size of low-dimensional SnTe nanostructures such as nanoribbons (1D) and nanoflakes (0D) using first-principle density-functional theory calculations. We demonstrate that the smallest (one-unit-cell width) SnTe nanoribbon can sustain ferroelectricity and there is no ferroelectric critical size in the SnTe nanoribbons. On the other hand, the SnTe nanoflakes form a vortex of polarization and lose their toroidal ferroelectricity below the surface area of 4 × 4 unit cells (about 25 Å on one side). We also reveal the atomic and electronic mechanism of the absence or presence of critical size in SnTe low-dimensional nanostructures. Our result provides an insight into intrinsic ferroelectric critical size for low-dimensional chalcogenide layered materials.

Low-Dimensional Topology and Number Theory

2010 ◽  
pp. 2101-2163 ◽  
Author(s):  
Paul Gunnells ◽  
Walter Neumann ◽  
Adam Sikora ◽  
Don Zagier
Keyword(s):  
Number Theory ◽  
Low Dimensional Topology ◽  
Low Dimensional

scholarly journals Valence Band Modification and High Thermoelectric Performance in SnTe Heavily Alloyed with MnTe

2015 ◽  
Vol 137 (35) ◽  
pp. 11507-11516 ◽  
Author(s):  
Gangjian Tan ◽  
Fengyuan Shi ◽  
Shiqiang Hao ◽  
Hang Chi ◽  
Trevor P. Bailey ◽  
...  
Keyword(s):  
Valence Band ◽  
Thermoelectric Performance
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