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The direct simulation of the dynamics of second sound in graphitic materials remains a challenging task due to lack of methodology for solving the phonon Boltzmann equation in such a stiff hydrodynamic regime. In this work, we aim to tackle…

Computational Physics · Physics 2019-10-09 Xiao-Ping Luo , Yang-Yu Guo , Mo-Ran Wang , Hong-Liang Yi

Acoustic waves in a linear time-invariant medium are generally reciprocal; however, reciprocity can break down in a time-variant system. In this Letter, we report on an experimental demonstration of nonreciprocity in a dynamic…

Applied Physics · Physics 2018-11-14 Yifan Wang , Behrooz Yousefzadeh , Hui Chen , Hussein Nassar , Guoliang Huang , Chiara Daraio

Understanding and predicting the thermodynamic properties of point defects in semiconductors and insulators would greatly aid in the design of novel materials and allow tuning the properties of existing ones. As a matter of fact,…

Materials Science · Physics 2021-04-07 Marco Arrigoni , Georg K. H. Madsen

Taking into account the constraints imposed by the lattice symmetry, we calculate the phonon dispersion for graphene with interactions between the first, second, and third nearest neighbors in the framework of the Born--von Karman model.…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 L. A. Falkovsky

Anharmonic lattice vibrations govern the thermal dynamics in materials and present how the atoms interact and how they conduct heat. An indepth understanding of the microscopic mechanism of phonon anharmonicity in condensed systems is…

Materials Science · Physics 2021-12-30 Bin Wei , Qiyang Sun , Chen Li , Jiawang Hong

Strain engineering has been extended recently to the ultrafast timescales, driving metal-insulator phase transitions and the propagation of ultrasonic demagnetization fronts. However, the non-linear lattice dynamics underpinning interfacial…

Materials Science · Physics 2021-01-13 J. R. Hortensius , D. Afanasiev , A. Sasani , E. Bousquet , A. D. Caviglia

We compute the phonon dispersion, density of states, and the Gr\"uneisen parameters of bulk palladium in the combined density functional theory (DFT) and dynamical mean-field theory (DMFT). We find good agreement with experimental results…

Strongly Correlated Electrons · Physics 2020-02-20 W. H. Appelt , A. Östlin , I. Di Marco , I. Leonov , M. Sekania , D. Vollhardt , L. Chioncel

The existing techniques of account for the phonon dispersion are computationally costly, while its impact on a variety of thermodynamic properties appears negligible. We develop a mathematical formalism, which allows for clear understanding…

Statistical Mechanics · Physics 2014-05-01 Roman Belousov , Mauro Prencipe

By means of first-principles calculations, various properties of SrRuO3 are investigated, focusing on its lattice dynamical properties. Despite having a Goldschmidt tolerance factor very close to 1, the phonon dispersion curves of the…

Materials Science · Physics 2015-03-09 Naihua Miao , Nicholas C Bristowe , Bin Xu , Matthieu Verstraete , Philippe Ghosez

Classical density functional theory (DFT) is a statistical mechanical theory for calculating the density profiles of the molecules in a liquid. It is widely used, for example. to calculate the density distribution of the molecules in the…

Statistical Mechanics · Physics 2015-07-08 Adam P. Hughes , Uwe Thiele , Andrew J. Archer

The search for new physics requires a joint experimental and theoretical effort. Lattice QCD is already an essential tool for obtaining precise model-free theoretical predictions of the hadronic processes underlying many key experimental…

The lattice dynamics of the metallic tin {\beta} and {\gamma} polymorphs has been studied by a combination of diffuse scattering, inelastic x-ray scattering and density functional perturbation theory. The non-symmorphic space group of the…

Understanding phonon scattering by topological defects in graphene is of particular interest for thermal management in graphene-based devices. We present a study that quantifies the roles of the different mechanisms governing defect phonon…

Materials Science · Physics 2016-11-04 Ziming Zhu , Xiaolong Yang , Mingyuan Huang , Qingfeng He , Guang Yang , Zhao Wang

Correlation functions, such as static and dynamic structure factors, offer a versatile approach to analyzing atomic-scale structure and dynamics. By having access to the full dynamics from atomistic simulations, they serve as valuable tools…

In the present paper, DFT (Density Functional Theory) based first-principles methods are applied to investigate the mechanical and bonding properties of newly synthesized T2 phase superconductor Ta5GeB2 for the first time. The calculated…

Materials Science · Physics 2016-11-03 M. A. Hadi , M. T. Nasir , M. Roknuzzaman , M. A. Rayhan , S. H. Naqib , A. K. M. A. Islam

We investigate the binding surface along the Bain path and phonon dispersion relations for the cubic phase of the ferromagnetic binary alloys Fe3X (X = Ni, Pd, Pt) for L12 and DO22 ordered phases from first principles by means of density…

Materials Science · Physics 2011-11-28 Markus E. Gruner , Waheed A. Adeagbo , Alexey T. Zayak , Alfred Hucht , Peter Entel

In this work, we investigate the dynamics of interacting particle systems subjected to repulsive forces, such as lattices of magnetized particles. To this end, we first develop a general model capable of capturing the complete dynamical…

Applied Physics · Physics 2021-03-22 Weijian Jiao , Stefano Gonella

Phonons, the quantum mechanical representation of lattice vibrations, and their coupling to the electronic degrees of freedom are important for understanding thermal and electric properties of materials. For the first time, phonons have…

Strongly Correlated Electrons · Physics 2011-01-25 H. Yavas , M. van Veenendaal , J. van den Brink , L. J. P. Ament , A. Alatas , B. M. Leu , M. -O. Apostu , N. Wizent , G. Behr , W. Sturhahn , H. Sinn , E. E. Alp

The package "fhi96md" is an efficient code to perform density-functional theory total-energy calculations for materials ranging from insulators to transition metals. The package employs first-principles pseudopotentials, and a plane-wave…

Condensed Matter · Physics 2009-10-30 Michel Bockstedte , Alexander Kley , Joerg Neugebauer , Matthias Scheffler

We extend density functional perturbation theory for lattice dynamics with fully relativistic ultrasoft pseudopotentials to magnetic materials. Our approach is based on the application of the time-reversal operator to the Sternheimer linear…

Computational Physics · Physics 2019-07-24 Andrea Urru , Andrea Dal Corso