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Related papers: DynaPhoPy: A code for extracting phonon quasiparti…

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Extensive inelastic neutron scattering measurements of phonons on a single crystal of CaFe2As2 allowed us to establish a fairly complete picture of phonon dispersions in the main symmetry directions. The phonon spectra were also calculated…

Coupling to phonon modes is a primary mechanism of excitonic dephasing and energy loss in semiconductors. However, low-energy phonons in colloidal quantum dots and their coupling to excitons are poorly understood, since their experimental…

Mesoscale and Nanoscale Physics · Physics 2019-10-22 Albert Liu , Diogo B. Almeida , Wan-Ki Bae , Lazaro A. Padilha , Steven T. Cundiff

It appears feasible with nanostructures to perform calorimetry at the level of individual thermal phonons. Here I outline an approach employing monocrystalline mesoscopic insulators, which can now be patterned from semiconductor…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 M. L. Roukes

We study the relaxation of coherent acoustic phonon modes with frequencies up to 500 GHz in ultra-thin free-standing silicon membranes. Using an ultrafast pump-probe technique of asynchronous optical sampling, we observe that the decay time…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 J. Cuffe , O. Ristow , E. Chávez , A. Shchepetov , P-O. Chapuis , F. Alzina , M. Hettich , M. Prunnila , J. Ahopelto , T. Dekorsy , C. M. Sotomayor Torres

Perturbative treatments of the lattice dynamics are widely successful for many crystalline materials, their applicability is, however, limited for strongly anharmonic systems, metastable crystal structures and liquids. The full dynamics of…

Materials Science · Physics 2023-10-10 Erik Fransson , Mattias Slabanja , Paul Erhart , Göran Wahnström

In recent years, nanostructuring of dielectric and semiconducting crystals has enhanced controllability of their thermal conductivity. To carry out computational material search for nanostructured materials with desirable thermal…

Mesoscale and Nanoscale Physics · Physics 2016-02-23 Takuma Shiga , Daisuke Aketo , Lei Feng , Junichiro Shiomi

The thermal dynamics induced by ultrashort laser pulses in nanoscale systems, i.e. all-optical time-resolved nanocalorimetry is theoretically investigated from 300 to 1.5 K. We report ab-initio calculations describing the temperature…

Mesoscale and Nanoscale Physics · Physics 2015-03-13 F. Banfi , F. Pressacco , B. Revaz , C. Giannetti , D. Nardi , G. Ferrini , F. Parmigiani

Recently, Dammak and coworkers (H. Dammak, Y. Chalopin, M. Laroche, M. Hayoun, and J.J. Greffet. Quantumthermal bath for molecular dynamics simulation. Phys. Rev. Lett., 103:190601, 2009.) proposed that the quantum statistics of vibrations…

Materials Science · Physics 2011-05-30 Jean-Louis Barrat , David Rodney

We present an \textit{ab initio} framework to calculate anharmonic phonon frequency and phonon lifetime that is applicable to severely anharmonic systems. We employ self-consistent phonon (SCPH) theory with microscopic anharmonic force…

Materials Science · Physics 2015-08-20 Terumasa Tadano , Shinji Tsuneyuki

The properties of the intramolecular vibrational excitation (vibron) in a quasi 1D macromolecular structure are studied. It is supposed that due to the vibron interaction with optical phonon modes, a vibron might form partially dressed…

Mesoscale and Nanoscale Physics · Physics 2018-02-22 D. Cevizovic , A. Chizhov , A. Reshetnyak , Z. Ivic , S. Galovic , S. Petkovic

We present a computer program to calculate the quantised rotational and hyperfine energy levels of $^{1}\Sigma $ diatomic molecules in the presence of dc electric, dc magnetic, and off-resonant optical fields. Our program is applicable to…

Computational Physics · Physics 2022-09-28 Jacob A. Blackmore , Philip D. Gregory , Jeremy M. Hutson , Simon L. Cornish

Phonons play a critical role in determining various material properties, but conventional methods for phonon calculations are computationally intensive, limiting their broad applicability. In this study, we present an approach to accelerate…

Materials Science · Physics 2024-07-16 Huiju Lee , Vinay I. Hegde , Chris Wolverton , Yi Xia

Metal-organic frameworks (MOFs) are highly porous and versatile materials studied extensively for applications such as carbon capture and water harvesting. However, computing phonon-mediated properties in MOFs, like thermal expansion and…

Harnessing the power of low-dimensional materials in thermal applications calls for a solid understanding of the anomalous thermal properties of such systems. We analyze thermal conduction in one-dimensional systems by determining the…

Computational Physics · Physics 2015-12-21 K. Sääskilahti , J. Oksanen , S. Volz , J. Tulkki

Scientific simulation codes are public property sustained by the community. Modern technology allows anyone to join scientific software projects, from anywhere, remotely via the internet. The phonopy and phono3py codes are widely used open…

Materials Science · Physics 2023-06-14 Atsushi Togo , Laurent Chaput , Terumasa Tadano , Isao Tanaka

Self-consistent phonon (SCP) theory and its application in computing thermodynamic properties of materials are reviewed from a historical perspective. Various more recent implementations based on first-principles electronic structure…

Materials Science · Physics 2019-11-05 Keivan Esfarjani , Yuan Liang

Despite recent progress in the first-principles calculations and measurements of phonon mean-free-paths (MFPs), contribution of low-energy phonons to heat conduction in silicon is still inconclusive, as exemplified by the discrepancies…

Materials Science · Physics 2018-05-18 Puqing Jiang , Yee Kan Koh

We report the development of a forcefield capable of reproducing accurate lattice dynamics of metal-organic frameworks. Phonon spectra, thermodynamic and mechanical properties, such as free energies, heat capacities and bulk moduli, are…

Materials Science · Physics 2016-10-28 J. K. Bristow , J. M. Skelton , K. L. Svane , A. Walsh , J. D. Gale

The phonon-assisted interband optical absorption spectrum of silicon is calculated at the quasiparticle level entirely from first principles. We make use of the Wannier interpolation formalism to determine the quasiparticle energies, as…

Phonon quasi-particles have been monumental in microscopically understanding thermodynamics and transport properties in condensed matter for decades. Phonons have one-to-one correspondence with harmonic eigenstates and their energies are…

Materials Science · Physics 2024-08-27 Jaeyun Moon , Leo Zella , Lucas Lindsay