scholarly journals Oxidation-enhanced thermoelectric efficiency in a two-dimensional phosphorene oxide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seungjun Lee ◽  
Jeong-Pil Song ◽  
Seoung-Hun Kang ◽  
Young-Kyun Kwon
Keyword(s):  
Thermoelectric Properties ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Thermoelectric Performance ◽  
Boltzmann Transport ◽  
Thermoelectric Efficiency ◽  
Electron Phonon Interaction ◽  
Electron Relaxation Time ◽  
Low Dimensional ◽  
Spontaneous Oxidation

AbstractWe performed density functional theory calculations to investigate the thermoelectric properties of phosphorene oxide (PO) expected to form by spontaneous oxidation of phosphorene. Since thermoelectric features by nature arise from the consequences of the electron-phonon interaction, we computed the phonon-mediated electron relaxation time, which was fed into the semiclassical Boltzmann transport equation to be solved for various thermoelectric-related quantities. It was found that PO exhibits superior thermoelectric performance compared with its pristine counterpart, which has been proposed to be a candidate for the use of future thermoelectric applications. We revealed that spontaneous oxidation of phosphorene leads to a significant enhancement in the thermoelectric properties of n-doped phosphorene oxide, which is attributed to the considerable reduction of lattice thermal conductivity albeit a small decrease in electrical conductivity. Our results suggest that controlling oxidation may be utilized to improve thermoelectric performance in nanostructures, and PO can be a promising candidate for low-dimensional thermoelectric devices.

scholarly journals Enhanced mechanism of thermoelectric performance of Bi2Se3 using density functional theory

2020 ◽  
Vol 9 (3) ◽  
Author(s):  
Muhammad Zamir Mohyedin ◽  
Mohamad Fariz Mohamad Taib ◽  
Afiq Radzwan ◽  
M. Mustaffa ◽  
Amiruddin Shaari ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Effective Mass ◽  
Thermoelectric Properties ◽  
Density Of States ◽  
Power Factor ◽  
Figure Of Merit ◽  
Density Functional ◽  
Thermoelectric Performance ◽  
Boltzmann Transport ◽  
Functional Theory

Abstract Good thermoelectric performance is being sought to face major problems related to energy, especially in the concern of the usage of energy on environmental impact. In this work, we investigate the underlying mechanism to enhance the thermoelectric performance of bismuth selenide (Bi2Se3) by employing density functional theory (DFT) followed by the Boltzmann transport equation under relaxation time approximation. The structural, electronic, and thermoelectric properties were calculated and analyzed. From the analysis of combined results of thermoelectric properties and electronic properties as the function of the Fermi level, we found that the power factor of Bi2Se3 is improved by increasing electrical conductivity that contributed by the large density of states and light effective mass of charge carriers. The figure of merit, on the other hand, is enhanced by increasing Seebeck coefficient that contributed by heavy effective mass and decreasing thermal conductivity that contributed by low density of states. We also found that both power factor and figure of merit can be improved through n-type doping at 300 K and p-type doping at higher temperature (400 K and 500 K).

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.

Ab-initio study of mechanical and thermoelectric properties of topological semimetal: LaAuPb

2021 ◽  
Author(s):  
Megha Goyal ◽  
M.M. Sinha
Keyword(s):  
Thermoelectric Properties ◽  
Density Functional ◽  
Transport Theory ◽  
Poisson Ratio ◽  
Topological Phase ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
Boltzmann Transport Theory ◽  
Material Fabrication ◽  
The Stability

Abstract Heusler compounds are a tuneable class of material with a cubic crystal structure that can serve as a platform to study the topological phase of a material. These materials have numerous technological and scientific applications. So, in the present work, the mechanical, thermodynamical, and thermoelectric properties of LaAuPb in the topological phase have been reported by using density functional theory and Boltzmann transport theory. LaAuPb is mechanically stable, and the Poisson ratio reveals its ductile nature. The specific heat of the proposed compound at room temperature is 73.94 J K-1 mol-1 at constant volume. Debye’s temperature is estimated to be 188.64K. Moreover, the lattice thermal conductivity of the compound is 14.64 W/mK and 3.66 W/mK at 300K and 1200K, respectively. Good thermoelectric response of LaAuPb can be confirmed by its high value of the figure of merit (0.46) at 1200K. Hence, it is a potential material for thermoelectric applications. This work will help future researchers to better understand the stability, nature and behaviour of LaAuPb in material fabrication.

A High Thermoelectric Performance ZT in p-Type LaSe2 Crystal

2021 ◽  
Vol 871 ◽  
pp. 203-207
Author(s):  
Jian Liu
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
High Power ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Thermoelectric Performance ◽  
Boltzmann Transport ◽  
High Power Factor ◽  
P Type

In this work, we use first principles DFT calculations, anharmonic phonon scatter theory and Boltzmann transport method, to predict a comprehensive study on the thermoelectric properties as electronic and phonon transport of layered LaSe2 crystal. The flat-and-dispersive type band structure of LaSe2 crystal offers a high power factor. In the other hand, low lattice thermal conductivity is revealed in LaSe2 semiconductor, combined with its high power factor, the LaSe2 crystal is considered a promising thermoelectric material. It is demonstrated that p-type LaSe2 could be optimized to exhibit outstanding thermoelectric performance with a maximum ZT value of 1.41 at 1100K. Explored by density functional theory calculations, the high ZT value is due to its high Seebeck coefficient S, high electrical conductivity, and low lattice thermal conductivity .

The n- and p-type thermoelectric response of a semiconducting Co-based quaternary Heusler alloy: a density functional approach

2019 ◽  
Vol 7 (25) ◽  
pp. 7664-7671 ◽  
Author(s):  
Enamullah Enamullah ◽  
Pil-Ryung Cha
Keyword(s):  
Electronic Structure ◽  
Thermoelectric Properties ◽  
Heusler Alloy ◽  
Density Functional ◽  
Transport Theory ◽  
Mechanical Stability ◽  
Functional Approach ◽  
Boltzmann Transport ◽  
Boltzmann Transport Theory ◽  
P Type

In the combined framework of density functional and Boltzmann transport theory, we have systematically studied the electronic structure, mechanical stability and thermoelectric properties of the semiconducting quaternary Heusler alloy, CoFeTiAl.

scholarly journals Electronic, optical and thermoelectric properties of Fe2ZrP compound determined via first-principles calculations

RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25900-25911 ◽  
Author(s):  
Esmaeil Pakizeh ◽  
Jaafar Jalilian ◽  
Mahnaz Mohammadi
Keyword(s):  
Density Functional Theory ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Density Functional ◽  
Transport Theory ◽  
First Principles Calculations ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
Boltzmann Transport Theory ◽  
The Density Functional Theory

In this study, based on the density functional theory and semi-classical Boltzmann transport theory, we investigated the structural, thermoelectric, optical and phononic properties of the Fe2ZrP compound.

Hybrid functional calculations of electronic and thermoelectric properties of GaS, GaSe, and GaTe monolayers

2018 ◽  
Vol 20 (45) ◽  
pp. 28575-28582 ◽  
Author(s):  
Bhagwati Prasad Bahuguna ◽  
L. K. Saini ◽  
Rajesh O. Sharma ◽  
Brajesh Tiwari
Keyword(s):  
Density Functional Theory ◽  
Transport Equation ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Density Functional ◽  
Boltzmann Transport Equation ◽  
Boltzmann Transport ◽  
Hybrid Functional ◽  
Functional Theory

We have investigated the structural, electronic and thermoelectric properties of GaS, GaSe and GaTe monolayers based on the first-principles approach by using density functional theory and the semi-classical Boltzmann transport equation.

scholarly journals Atomic origin of spin-valve magnetoresistance at the SrRuO3 grain boundary

2020 ◽  
Vol 7 (4) ◽  
pp. 755-762 ◽  
Author(s):  
Xujing Li ◽  
Li Yin ◽  
Zhengxun Lai ◽  
Mei Wu ◽  
Yu Sheng ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Density Functional ◽  
Magnetic Moments ◽  
Spin Valve ◽  
Density Functional Theory Calculations ◽  
Precise Knowledge ◽  
Transmission Electron ◽  
Defect Control ◽  
Scanning Transmission ◽  
Low Dimensional

Abstract Defects exist ubiquitously in crystal materials, and usually exhibit a very different nature from the bulk matrix. Hence, their presence can have significant impacts on the properties of devices. Although it is well accepted that the properties of defects are determined by their unique atomic environments, the precise knowledge of such relationships is far from clear for most oxides because of the complexity of defects and difficulties in characterization. Here, we fabricate a 36.8° SrRuO3 grain boundary of which the transport measurements show a spin-valve magnetoresistance. We identify its atomic arrangement, including oxygen, using scanning transmission electron microscopy and spectroscopy. Based on the as-obtained atomic structure, the density functional theory calculations suggest that the spin-valve magnetoresistance occurs because of dramatically reduced magnetic moments at the boundary. The ability to manipulate magnetic properties at the nanometer scale via defect control allows new strategies to design magnetic/electronic devices with low-dimensional magnetic order.

scholarly journals High thermoelectric performance of the distorted bismuth(110) layer

2016 ◽  
Vol 18 (26) ◽  
pp. 17373-17379 ◽  
Author(s):  
L. Cheng ◽  
H. J. Liu ◽  
J. Zhang ◽  
J. Wei ◽  
J. H. Liang ◽  
...  
Keyword(s):  
Transport Equation ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Boltzmann Transport Equation ◽  
Thermoelectric Performance ◽  
First Principles Calculations ◽  
Boltzmann Transport

The thermoelectric properties of the distorted bismuth(110) layer are investigated using first-principles calculations combined with the Boltzmann transport equation for both electrons and phonons.

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