Janus monolayer of WSeTe, a new structural phase transition material driven by electrostatic gating

The nature of the structural phase transition in the quantum magnets barlowite, Cu4(OH)6FBr, and claringbullite, Cu4(OH)6FCl was investigated. These materials consist of parallel-stacked Cu2+ kagome layers, separated by planes that contain Cu2+ cations and halide anions. The structural transition is of an order-disorder type, where at ambient temperature the interlayer Cu2+ ions are disordered over three equivalent positions. In barlowite, the dynamic disorder becomes static as the temperature is decreased, resulting in a lowering of the overall symmetry from hexagonal P63/mmc to orthorhombic. The dynamic disorder in claringbullite persists to lower temperatures, with a transition to orthorhombic space group Pnma observed in some samples. Ab initio density functional theory calculations explain this temperature-dependent structural phase transition and provide additional insights regarding the differences between these two materials.

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Dynamic Order-Disorder Transition in the S = ½ Kagome Antiferromagnets Barlowite and Claringbullite

10.26434/chemrxiv.7468070 ◽

2018 ◽

Author(s):

Alyssa Henderson ◽

Lianyang Dong ◽

Sananda Biswas ◽

Hannah Revell ◽

Yan Xin ◽

...

Keyword(s):

Phase Transition ◽

Structural Phase Transition ◽

Density Functional ◽

Structural Phase ◽

Density Functional Theory Calculations ◽

Temperature Dependent ◽

Orthorhombic Space Group ◽

Functional Theory ◽

Dynamic Disorder ◽

Disorder Type

The nature of the structural phase transition in the quantum magnets barlowite, Cu4(OH)6FBr, and claringbullite, Cu4(OH)6FCl was investigated. These materials consist of parallel-stacked Cu2+ kagome layers, separated by planes that contain Cu2+ cations and halide anions. The structural transition is of an order-disorder type, where at ambient temperature the interlayer Cu2+ ions are disordered over three equivalent positions. In barlowite, the dynamic disorder becomes static as the temperature is decreased, resulting in a lowering of the overall symmetry from hexagonal P63/mmc to orthorhombic. The dynamic disorder in claringbullite persists to lower temperatures, with a transition to orthorhombic space group Pnma observed in some samples. Ab initio density functional theory calculations explain this temperature-dependent structural phase transition and provide additional insights regarding the differences between these two materials.

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Predicted polymorph manipulation in an exotic double perovskite oxide

Journal of Materials Chemistry C ◽

10.1039/c9tc03367j ◽

2019 ◽

Vol 7 (39) ◽

pp. 12306-12311 ◽

Cited By ~ 4

Author(s):

He-Ping Su ◽

Shu-Fang Li ◽

Yifeng Han ◽

Mei-Xia Wu ◽

Churen Gui ◽

...

Keyword(s):

Phase Transition ◽

Density Functional Theory ◽

First Principles ◽

Density Functional ◽

Double Perovskite ◽

Density Functional Theory Calculations ◽

Perovskite Oxide ◽

Functional Theory ◽

First Time ◽

Perovskite Type

First-principles density functional theory calculations, for the first time, was used to predict the Mg3TeO6-to-perovskite type phase transition in Mn3TeO6 at around 5 GPa.

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DFT Calculations of the Structural, Mechanical, and Electronic Properties of TiV Alloy Under High Pressure

Symmetry ◽

10.3390/sym11080972 ◽

2019 ◽

Vol 11 (8) ◽

pp. 972 ◽

Cited By ~ 1

Author(s):

Fang Yu ◽

Yu Liu

Keyword(s):

Phase Transition ◽

High Pressure ◽

Electronic Properties ◽

Structural Phase Transition ◽

Density Functional ◽

Structural Phase ◽

Applied Pressure ◽

Functional Theory ◽

The Density Functional Theory ◽

Dimensionless Ratio

A calculation program based on the density functional theory (DFT) is applied to study the structural, mechanical, and electronic properties of TiV alloys with symmetric structure under high pressure. We calculate the dimensionless ratio, elastic constants, shear modulus, Young’s modulus, bulk modulus, ductile-brittle transition, material anisotropy, and Poisson’s ratio as functions of applied pressure. Results suggest that the critical pressure of structural phase transition is 42.05 GPa for the TiV alloy, and structural phase transition occurs when the applied pressure exceeds 42.05 GPa. High pressure can improve resistance to volume change, as well as the ductility and atomic bonding, but the strongest resistances to elastic and shear deformation occur at P = 5 GPa for TiV alloy. Furthermore, the results of the density of states (DOS) indicate that the TiV alloy presents metallicity. High pressure disrupts the structural stability of the TiV alloy with symmetry, thereby inducing structural phase transition.

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Crossover from metal to insulator in dense lithium-rich compound CLi4

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1525412113 ◽

2016 ◽

Vol 113 (9) ◽

pp. 2366-2369 ◽

Cited By ~ 10

Author(s):

Xilian Jin ◽

Xiao-Jia Chen ◽

Tian Cui ◽

Ho-kwang Mao ◽

Huadi Zhang ◽

...

Keyword(s):

Phase Transition ◽

Density Functional Theory ◽

Fermi Surface ◽

Density Functional ◽

Alkali Metals ◽

Alkaline Earth ◽

Density Functional Theory Calculations ◽

Alkaline Earth Metals ◽

Functional Theory ◽

Surface Filling

At room environment, all materials can be classified as insulators or metals or in-between semiconductors, by judging whether they are capable of conducting the flow of electrons. One can expect an insulator to convert into a metal and to remain in this state upon further compression, i.e., pressure-induced metallization. Some exceptions were reported recently in elementary metals such as all of the alkali metals and heavy alkaline earth metals (Ca, Sr, and Ba). Here we show that a compound of CLi4 becomes progressively less conductive and eventually insulating upon compression based on ab initio density-functional theory calculations. An unusual path with pressure is found for the phase transition from metal to semimetal, to semiconductor, and eventually to insulator. The Fermi surface filling parameter is used to describe such an antimetallization process.

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Electronic and Optical Properties of Sodium Niobate: A Density Functional Theory Study

Advances in Materials Science and Engineering ◽

10.1155/2018/6416057 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Daniel Fritsch

Keyword(s):

Density Functional Theory ◽

Optical Properties ◽

Lead Zirconate Titanate ◽

Density Functional ◽

Room Temperature ◽

Structural Phase ◽

Density Functional Theory Calculations ◽

Sodium Niobate ◽

Functional Theory ◽

Electronic And Optical Properties

In recent years, much effort has been devoted to replace the most commonly used piezoelectric ceramic lead zirconate titanate Pb[ZrxTi1−x]O3 (PZT) with a suitable lead-free alternative for memory or piezoelectric applications. One possible alternative to PZT is sodium niobate as it exhibits electrical and mechanical properties that make it an interesting material for technological applications. The high-temperature simple cubic perovskite structure undergoes a series of structural phase transitions with decreasing temperature. However, particularly the phases at room temperature and below are not yet fully characterised and understood. Here, we perform density functional theory calculations for the possible phases at room temperature and below and report on the structural, electronic, and optical properties of the different phases in comparison to experimental findings.

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THEORETICAL EVIDENCE FOR UNUSUAL BONDING GEOMETRY AND PHASE TRANSITIONS OF Na ON Al(001)

Surface Review and Letters ◽

10.1142/s0218625x94000217 ◽

1994 ◽

Vol 01 (02n03) ◽

pp. 213-219 ◽

Cited By ~ 27

Author(s):

C. STAMPFL ◽

J. NEUGEBAUER ◽

M. SCHEFFLER

Keyword(s):

Phase Transition ◽

Density Functional Theory ◽

Phase Transitions ◽

Density Functional ◽

Alkali Metals ◽

Density Functional Theory Calculations ◽

Functional Theory ◽

Island Formation ◽

Low Concentration ◽

Theoretical Evidence

We performed density-functional theory calculations for Na on Al(001) for various coverages from a very low concentration up to a monolayer. From the results we predict that for low coverages the Na atoms occupy on-surface hollow sites which is the stable geometry, but for higher coverages this is only metastable; the stable geometry is reached through a phase transition to a condensed c(2×2) structure where the Na atoms are in surface substitutional sites (contrary to previously suggested models). The mechanism which actuates the island formation with a substitutional geometry is described and the differences to the substitutional adsorption of alkali metals on Al(111) are discussed.

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Revised prediction of B1 to B2 phase transition pressures in YbN, YbP and YbAs

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1524/zkri.220.8.700.67080 ◽

2005 ◽

Vol 220 (8) ◽

Cited By ~ 3

Author(s):

Björn Winkler ◽

Victor Milman

Keyword(s):

Phase Transition ◽

Density Functional Theory ◽

Density Functional ◽

Structural Phase ◽

Quantum Mechanical ◽

Quantum Mechanical Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Model Calculations ◽

B2 Phase

AbstractQuantum mechanical calculations based on density functional theory and a generalized gradient approx imation have been used to study the pressure-induced B1 to B2 structural phase transition in YbN, YbP and YbAs. The phase transitions are predicted to occur at 137 GPa in YbN, at 25 GPa in YbP, and at 20 GPa in YbAs. These values are significantly lower than those predicted by empirical poten tial model calculations. Bulk moduli are predicted to be 136, 70 and 63 GPa for YbN, YbP and YbAs, respectively.

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