Temperature-dependent renormalization of magnetic interactions by thermal, magnetic, and lattice disorder from first principles

2021 ◽  
Vol 103 (18) ◽  
Author(s):  
Matthew Heine ◽  
Olle Hellman ◽  
David Broido
Keyword(s):  
First Principles ◽  
Magnetic Interactions ◽  
Temperature Dependent ◽  
Lattice Disorder

scholarly journals Free Energy of Metals from Quasi-Harmonic Models of Thermal Disorder

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 195
Author(s):  
Pavel A. Korzhavyi ◽  
Jing Zhang
Keyword(s):  
Free Energy ◽  
First Principles ◽  
Density Functional ◽  
Helmholtz Free Energy ◽  
Complex Materials ◽  
Predictive Capability ◽  
Temperature Dependent ◽  
Disordered Alloys ◽  
Thermal Disorder ◽  
Structure Calculations

A simple modeling method to extend first-principles electronic structure calculations to finite temperatures is presented. The method is applicable to crystalline solids exhibiting complex thermal disorder and employs quasi-harmonic models to represent the vibrational and magnetic free energy contributions. The main outcome is the Helmholtz free energy, calculated as a function of volume and temperature, from which the other related thermophysical properties (such as temperature-dependent lattice and elastic constants) can be derived. Our test calculations for Fe, Ni, Ti, and W metals in the paramagnetic state at temperatures of up to 1600 K show that the predictive capability of the quasi-harmonic modeling approach is mainly limited by the electron density functional approximation used and, in the second place, by the neglect of higher-order anharmonic effects. The developed methodology is equally applicable to disordered alloys and ordered compounds and can therefore be useful in modeling realistically complex materials.

scholarly journals The thermal stability of FAPbBr3 nanocrystals from temperature-dependent photoluminescence and first-principles calculations

RSC Advances ◽  
2020 ◽  
Vol 10 (72) ◽  
pp. 44373-44381
Author(s):  
Xiaozhe Wang ◽  
Qi Wang ◽  
Zhijun Chai ◽  
Wenzhi Wu
Keyword(s):  
First Principles ◽  
First Principle ◽  
First Principles Calculations ◽  
Temperature Dependent ◽  
Time Resolved ◽  
First Principle Calculations ◽  
Steady State Time ◽  
Time Resolved Photoluminescence ◽  
Thermal Stability Of ◽  
Temperature Dependent Photoluminescence

The thermal properties of FAPbBr3 perovskite nanocrystals (PNCs) is investigated by use of temperature-dependent steady-state/time-resolved photoluminescence and first-principle calculations.

Direct versus Mediated Through-Space Magnetic Interactions: A First Principles, Bottom-Up Reinvestigation of the Magnetism of the Pyridyl-Verdazyl:Hydroquinone Molecular Co-Crystal

2006 ◽  
Vol 12 (15) ◽  
pp. 3995-4005 ◽  
Author(s):  
Joaquim Jornet ◽  
Mercè Deumal ◽  
Jordi Ribas-Ariño ◽  
Michael J. Bearpark ◽  
Michael A. Robb ◽  
...  
Keyword(s):  
First Principles ◽  
Magnetic Interactions ◽  
Bottom Up

scholarly journals First-principles generated mechanical property database for multi-component Al alloys: Focusing on Al-rich corner

2017 ◽  
Vol 53 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. Wang ◽  
Y. Du ◽  
X. Tao ◽  
Y. Ouyang ◽  
L. Zhang ◽  
...  
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Linear Thermal Expansion ◽  
Elastic Stiffness ◽  
Debye Model ◽  
Al Alloys ◽  
Processing Route ◽  
Temperature Dependent ◽  
Polycrystalline Aggregates ◽  
Strain Stress

Systematic first-principles calculations of the single crystal elastic stiffness constants (cij?s) and the polycrystalline aggregates including bulk modulus (B), shear modulus (G), Young?s modulus (E) have been performed for series binary and ternary Al compounds at 0 K. In addition, the temperature-dependent elastic properties for some technologically important phases are calculated. The cij?s are calculated by means of an efficient strain-stress method. Phonon density of states or Debye model is employed to calculate the linear thermal expansion, which is then used to calculate the temperature dependence of elastic properties. The calculated temperature-dependent elastic properties are compiled in the format of CALPHAD (CALculation of PHAse Diagram) type formula. The presently computed elastic properties for Al compounds are needed for simulation of microstructure evolution of commercial Al alloys during series of processing route.

Spin-manipulated phonon dynamics during magnetic phase transitions in triangular lattice antiferromagnet CuCr1−xMgxO2 semiconductor films

RSC Advances ◽  
2016 ◽  
Vol 6 (32) ◽  
pp. 27136-27142 ◽  
Author(s):  
Xurui Li ◽  
Junyong Wang ◽  
Jinzhong Zhang ◽  
Yawei Li ◽  
Zhigao Hu ◽  
...  
Keyword(s):  
Phase Transitions ◽  
First Principles ◽  
Magnetic Phase ◽  
Magnetic Phase Transitions ◽  
First Principles Calculations ◽  
Semiconductor Films ◽  
Temperature Dependent ◽  
Phonon Spectra ◽  
Phonon Dynamics ◽  
Triangular Lattice Antiferromagnet

The temperature-dependent phonon spectra and magnetoresistance of CuCr1−xMgxO2 films have been studied, combined with first-principles calculations.

Unusual interfacial magnetic interactions for τ-MnAl with Fe(Co) atomic layers

2019 ◽  
Vol 21 (5) ◽  
pp. 2443-2452 ◽  
Author(s):  
Junwei Tong ◽  
Yuxuan Feng ◽  
Fubo Tian ◽  
Lianqun Zhou ◽  
Gaowu Qin ◽  
...  
Keyword(s):  
First Principles ◽  
Magnetic Interaction ◽  
Magnetic Interactions ◽  
Coupling Mechanism ◽  
First Principles Calculations

The interfacial magnetic interaction and coupling mechanism for τ-MnAl with Fe(Co) atomic layers have been studied using first principles calculations.

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