scholarly journals Ternary superconducting cophosphorus hydrides stabilized via lithium

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Ziji Shao ◽  
Defang Duan ◽  
Yanbin Ma ◽  
Hongyu Yu ◽  
Hao Song ◽  
...  
Keyword(s):  
High Pressure ◽  
First Principles ◽  
Structure Prediction ◽  
Pressure Range ◽  
High Temperature Superconductor ◽  
High Pressures ◽  
Experimental Studies ◽  
First Principles Calculations ◽  
Ternary Compounds ◽  
Stable Structures

Abstract Inspired by the diverse properties of sulfur hydrides and phosphorus hydrides, we combine first-principles calculations with structure prediction to search for stable structures of Li−P−H ternary compounds at high pressures with the aim of finding novel superconductors. It is found that phosphorus hydrides can be stabilized under pressure via additional doped lithium. Four stable stoichiometries LiPH3, LiPH4, LiPH6, and LiPH7 are uncovered in the pressure range of 100–300 GPa. Notably, we find an atomic LiPH6 with $$Pm\overline 3$$ P m 3 ¯ symmetry which is predicted to be a potential high-temperature superconductor with a Tc value of 150–167 K at 200 GPa and the Tc decreases upon compression. All the predicted stable ternary hydrides contain the P–H covalent frameworks with ionic lithium staying beside, but not for $$Pm\overline 3$$ P m 3 ¯ -LiPH6. We proposed a possible synthesis route for ternary lithium phosphorus hydrides: LiP + H2 → LiPHn, which could provide helpful and clear guidance to further experimental studies. Our work may provide some advice on further investigations on ternary superconductive hydrides at high pressure.

scholarly journals Mechanical properties and band structure of CdSe and CdTe nanostructures at high pressure - a first-principles study

2019 ◽  
Vol 13 (2) ◽  
pp. 124-131 ◽  
Author(s):  
Natarajan Kishore ◽  
Veerappan Nagarajan ◽  
Ramanathan Chandiramouli
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Shear Modulus ◽  
Band Structure ◽  
First Principles ◽  
Pressure Range ◽  
Uniaxial Pressure ◽  
First Principles Calculations ◽  
Zinc Blende ◽  
Cauchy Pressure

First-principles calculations for CdSe and CdTe nanostructures were carried out to study their mechanical properties and band structure under the uniaxial pressure range of 0 to 50GPa. It was presumed that the CdSe and CdTe nanostructures exist in the zinc-blende phase under high pressure. The mechanical properties, such as elastic constants, bulk modulus, shear modulus and Young?s modulus, were explored. Furthermore, Cauchy pressure, Poisson?s ratio and Pugh?s criterion were studied under high pressure for both CdSe and CdTe nanostructures, and the results show that they exhibit ductile property. The band structure studies of CdSe and CdTe were also investigated. The findings show that the mechanical properties and the band structures of CdSe and CdTe can be tailored with high pressure.

Pressure effects on mechanical and electronic properties of metallic C14 by first-principles calculation

2019 ◽  
Vol 33 (18) ◽  
pp. 1950193
Author(s):  
Yingjiao Zhou ◽  
Qun Wei ◽  
Bing Wei ◽  
Ruike Yang ◽  
Ke Cheng ◽  
...  
Keyword(s):  
High Pressure ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Pressure Range ◽  
Phonon Dispersion ◽  
Elastic Anisotropy ◽  
Acoustic Velocity ◽  
Pressure Effects ◽  
First Principles Calculation ◽  
First Principles Calculations

The elastic constants and phonon dispersion of metallic C[Formula: see text] are calculated by first-principles calculations. The results show that the metallic C[Formula: see text] is mechanically and dynamically stable under high pressure. The variations of G/B ratio, Poisson’s ratio, elastic anisotropy, acoustic velocity and Debye temperature at the pressure range from 0 GPa to 100 GPa are analyzed. The results reveal that by adjusting the pressures the elastic anisotropy and thermodynamic properties could be improved for better applicability.

Low-pressure superconductivity in lithium-doped methane predicted by first principles

2020 ◽  
pp. 2150032
Author(s):  
Ning Lu ◽  
Yu-Long Hai ◽  
Hai-Yan Lv ◽  
Wen-Jie Li ◽  
Chun-Lei Yang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
High Temperature ◽  
Crystal Field ◽  
First Principles ◽  
Pressure Range ◽  
High Temperature Superconductor ◽  
Low Pressure ◽  
First Principles Calculations ◽  
A Charge ◽  
Low Pressures

To explore the high-temperature superconductor at low pressures, we have investigated the crystal structures, electronic properties, and possible superconductivity in the case of methane (CH4) doped by lithium in the pressure range of [Formula: see text][Formula: see text]GPa, based on the first-principles calculations. The results show that Li-intercalated CH4 (Lix(CH4)[Formula: see text]) can realize metallization and superconductivity at low pressures, even 5[Formula: see text]GPa. We find that there is a charge transfer between Li and CH4, but the metallization is driven by the change of crystal field induce by doping instead of charge transfer. The critical temperture is predicted from 3.8[Formula: see text]K at 5[Formula: see text]GPa for LiCH4 to 12.1[Formula: see text]K at 100[Formula: see text]GPa for Li(CH4)4. The low-pressure superconductivity of Lix(CH4)[Formula: see text] can be further optimized by adjusting component and pressure.

Theoretical studies of structural stability at high pressure

1995 ◽  
Vol 73 (5-6) ◽  
pp. 253-257 ◽  
Author(s):  
John S. Tse ◽  
Dennis D. Klug
Keyword(s):  
Molecular Dynamics ◽  
High Pressure ◽  
First Principles ◽  
High Pressures ◽  
Structural Phase ◽  
Md Simulations ◽  
Quantum Molecular Dynamics ◽  
First Principles Calculations ◽  
Quantum Mechanical Effects ◽  
Structural Memory

Theoretical methods are indispensible for the study of matter at high pressure. In the last decade the development of accurate intermolecular potentials and the methodologies in classical molecular dynamics (MD) simulations have greatly facililated the applications of these methods to the study of structural phase transformamtions of solids at high pressures. More recently, it has been possible to incorporate quantum mechanical effects into MD calculations. This method eliminates a great deal of empiricism. These first principles calculations have not only reproduced the experimental results for phase transformations but also provided detailed mechanisms and in some cases predicted new structures that may be found at high pressures. The success of MD calculations is illustrated through a review of our studies of pressure-induced amorphization and phase transitions in SiO2 and TiO2, and the structural memory effect in several materials. Current applications using quantum molecular dynamics on ice are discussed.

High-pressure phase transition of cesium chloride and cesium bromide

2014 ◽  
Vol 16 (33) ◽  
pp. 17924-17929 ◽  
Author(s):  
Shubo Wei ◽  
Chunye Zhu ◽  
Qian Li ◽  
Yuanyuan Zhou ◽  
Quan Li ◽  
...  
Keyword(s):  
High Pressure ◽  
First Principles ◽  
Structure Prediction ◽  
Cesium Chloride ◽  
Crystal Structure Prediction ◽  
First Principles Calculations ◽  
Phase Boundaries ◽  
Cesium Bromide ◽  
High Pressure Phase Transition ◽  
Pressure Phase

Using the CALYPSO method for crystal structure prediction combined with first-principles calculations, we have investigated the high-pressure crystal structures and established the corresponding phase boundaries for the prototypical AB-type compounds of CsCl and CsBr.

Mechanical Properties and Stability of Body-Centered-Tetragonal C8 at High Pressures

2018 ◽  
Vol 73 (10) ◽  
pp. 939-945
Author(s):  
Chenyang Zhao ◽  
Qun Wei ◽  
Haiyan Yan ◽  
Bing Wei
Keyword(s):  
Mechanical Properties ◽  
First Principles ◽  
Pressure Range ◽  
Superhard Material ◽  
High Pressures ◽  
Elastic Anisotropy ◽  
Acoustic Velocity ◽  
Large Strains ◽  
First Principles Calculations ◽  
The Ideal

AbstractThe structural, mechanical, electronic properties and stability of body-centered-tetragonal C8 (Bct-C8) were determined by using the first-principles calculations. Bct-C8 is identified to be mechanically and dynamically stable at a pressure range from 0 to 100 GPa. The elastic anisotropy, average acoustic velocity and Debye temperature of Bct-C8 at ambient and high pressures were studied. The ideal stresses at large strains of Bct-C8 were examined; the results showed that it would cleave under the tensile strength of 72 GPa or under the shear strength of 70 GPa, indicating that Bct-C8 is a potential superhard material.

scholarly journals Structural evolution of FeH4 under high pressure

RSC Advances ◽  
2017 ◽  
Vol 7 (21) ◽  
pp. 12570-12575 ◽  
Author(s):  
Fei Li ◽  
Dashuai Wang ◽  
Henan Du ◽  
Dan Zhou ◽  
Yanming Ma ◽  
...  
Keyword(s):  
High Pressure ◽  
First Principles ◽  
Pressure Range ◽  
Structural Evolution ◽  
Structural Search ◽  
Stable Structures

Here, we systematically investigated global energetically stable structures of FeH4 in the pressure range of 80–400 GPa using a first-principles structural search.

scholarly journals Compressed sodalite-like MgH6 as a potential high-temperature superconductor

RSC Advances ◽  
2015 ◽  
Vol 5 (73) ◽  
pp. 59292-59296 ◽  
Author(s):  
Xiaolei Feng ◽  
Jurong Zhang ◽  
Guoying Gao ◽  
Hanyu Liu ◽  
Hui Wang
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Critical Temperature ◽  
First Principles ◽  
High Temperature Superconductor ◽  
First Principles Calculations

First-principles calculations predicted a MgH6 phase with a high superconducting critical temperature of ∼260 K under high pressure.

First-principle study on ScAl3C3-type LaCd3P3 phases under high pressure

2020 ◽  
Vol 34 (29) ◽  
pp. 2050347
Author(s):  
Yufen Ren ◽  
Shiquan Feng ◽  
Chaosheng Yuan ◽  
Xuerui Cheng ◽  
Zuo Li
Keyword(s):  
High Pressure ◽  
Optical Properties ◽  
Thermal Properties ◽  
First Principles ◽  
High Pressures ◽  
Mechanical Stability ◽  
Pressure Effect ◽  
First Principle ◽  
First Principles Calculations ◽  
Debye Temperatures

Using first-principles calculations, we investigate the structural, electronic, thermal and optical properties of hexagonal ScAl3C3-type structure LaCd3P3 under high pressure. By calculating elastic constant, the mechanical stability of LaCd3P3 at high pressures was discussed. Then, by calculating the band gap and density of states, the pressure effect on electronic properties of LaCd3P3 was discussed. By calculating longitudinal, transverse sound, mean sound velocities, and the Debye temperatures at different pressures, the effect of pressure on thermal properties of LaCd3P3 was investigated. What is more, the dielectric function [Formula: see text] and reflectivity [Formula: see text] were calculated to explore the change of optical properties of LaCd3P3 under high pressure.

scholarly journals Structural and physical properties of 99 complex bulk chalcogenides crystals using first-principles calculations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahib Hasan ◽  
Khagendra Baral ◽  
Neng Li ◽  
Wai-Yim Ching
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
First Principles ◽  
Experimental Studies ◽  
First Principles Calculations ◽  
Chalcogenide Semiconductors ◽  
Optical And Mechanical Properties ◽  
Very Large Database ◽  
Unique Composition ◽  
Fundamental Physical

AbstractChalcogenide semiconductors and glasses have many applications in the civil and military fields, especially in relation to their electronic, optical and mechanical properties for energy conversion and in enviormental materials. However, they are much less systemically studied and their fundamental physical properties for a large class chalcogenide semiconductors are rather scattered and incomplete. Here, we present a detailed study using well defined first-principles calculations on the electronic structure, interatomic bonding, optical, and mechanical properties for 99 bulk chalcogenides including thirteen of these crytals which have never been calculated. Due to their unique composition and structures, these 99 bulk chalcogenides are divided into two main groups. The first group contains 54 quaternary crystals with the structure composition (A2BCQ4) (A = Ag, Cu; B = Zn, Cd, Hg, Mg, Sr, Ba; C = Si, Ge, Sn; Q = S, Se, Te), while the second group contains scattered ternary and quaternary chalcogenide crystals with a more diverse composition (AxByCzQn) (A = Ag, Cu, Ba, Cs, Li, Tl, K, Lu, Sr; B = Zn, Cd, Hg, Al, Ga, In, P, As, La, Lu, Pb, Cu, Ag; C = Si, Ge, Sn, As, Sb, Bi, Zr, Hf, Ga, In; Q = S, Se, Te; $$\hbox {x} = 1$$ x = 1 , 2, 3; $$\hbox {y} = 0$$ y = 0 , 1, 2, 5; $$\hbox {z} = 0$$ z = 0 , 1, 2 and $$\hbox {n} = 3$$ n = 3 , 4, 5, 6, 9). Moreover, the total bond order density (TBOD) is used as a single quantum mechanical metric to characterize the internal cohesion of these crystals enabling us to correlate them with the calculated properties, especially their mechanical properties. This work provides a very large database for bulk chalcogenides crucial for the future theoretical and experimental studies, opening opportunities for study the properties and potential application of a wide variety of chalcogenides.

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