Publications related to Debye model

Unearthing the foundational role of anharmonicity in heat transport in glasses

The time-honored Allen -Feldman theory of heat transport in glasses is generally assumed to predict a finite value for the thermal conductivity, even if it neglects the anharmonic broadening of vibrational normal modes. We demonstrate that the harmonic app ...

Amer Physical Soc2024

Interfacial Inversion, Interference, and IR Absorption in Vibrational Sum Frequency Scattering Experiments

Sylvie Roke, Saranya Pullanchery Sankara Narayanan, Lei Zhang, Sergey Kulik

Molecular interfacial structure greatly determines thepropertiesof nano- and microscale systems. Vibrational sum frequency scattering(SFS) spectroscopy is a unique interface-selective tool to measurethe interfacial vibrational spectrum of sub-micron to mic ...

AMER CHEMICAL SOC2023

Correlated insulator collapse due to quantum avalanche via in-gap ladder states

Xi Chen, Camille Didier Georges Aron

The significant discrepancy observed between the predicted and experimental switching fields in correlated insulators under a DC electric field far-from-equilibrium necessitates a reevaluation of current microscopic understanding. Here we show that an elec ...

Nature Portfolio2023

Koopmans Spectral Functionals in Periodic Boundary Conditions

Nicola Marzari, Nicola Colonna, Edward Baxter Linscott, Riccardo De Gennaro

Koopmans spectral functionals aim to describe simultaneously ground-state properties and charged excitations of atoms, molecules, nanostructures, and periodic crystals. This is achieved by augmenting standard density functionals with simple but physically ...

AMER CHEMICAL SOC2022

Evidence for a spin acoustic surface plasmon from inelastic atom scattering

Davide Campi

Closed-shell atoms scattered from a metal surface exchange energy and momentum with surface phonons mostly via the interposed surface valence electrons, i.e., via the creation of virtual electron-hole pairs. The latter can then decay into surface phonons v ...

Nature Research2021

Structural, electronic, elastic, power, and transport properties of beta-Ga2O3 from first principles

Samuel Poncé, Feliciano Giustino

We investigate the structural, electronic, vibrational, power, and transport properties of the beta allotrope of Ga2O3 from first principles. We find phonon frequencies and elastic constants that reproduce the correct band ordering, in agreement with exper ...

2020

Hubbard-corrected density functional perturbation theory with ultrasoft pseudopotentials

Nicola Marzari, Iurii Timrov, Matteo Cococcioni, Andrea Floris

We present in full detail a newly developed formalism enabling density functional perturbation theory (DFPT) calculations from a DFT + U ground state. The implementation includes ultrasoft pseudopotentials and is valid for both insulating and metallic syst ...

AMER PHYSICAL SOC2020

Balancing Density Functional Theory Interaction Energies in Charged Dimers Precursors to Organic Semiconductors

Anne-Clémence Corminboeuf, Alberto Fabrizio, Riccardo Petraglia

The pursuit of an increasingly accurate description of intermolecular interactions within the framework of Kohn-Sham density functional theory (KS-DFT) has motivated the construction of numerous benchmark databases over the past two decades. By far, the la ...

AMER CHEMICAL SOC2020

Time-reversal symmetry breaking Abelian chiral spin liquid in Mott phases of three-component fermions on the triangular lattice

Frédéric Mila, Karlo Penc, Pierre Marcel Nataf, Miklos Lajko, Carolin Boos

We provide numerical evidence in favor of spontaneous chiral symmetry breaking and the concomitant appearance of an Abelian chiral spin liquid for three-component fermions on the triangular lattice described by an SU(3) symmetric Hubbard model with hopping ...

2020

Phonon origin and lattice evolution in charge density wave states

Helmuth Berger

Metallic transition metal dichalcogenides, such as tantalum diselenide (TaSe2), display quantum correlated phenomena of superconductivity and charge density waves (CDWs) at low temperatures. Here, the photophysics of 2H-TaSe2 during CDW transitions is reve ...

AMER PHYSICAL SOC2019

Unified picture of lattice instabilities in metallic transition metal dichalcogenides

Oleg Yazyev, Diego José Pasquier

Transition metal dichalcogenides (TMDs) in the 1T polymorph are subject to a rich variety of periodic lattice distortions, often referred to as charge-density waves (CDWs) when not too strong. We study from first principles the fermiology and phonon disper ...

AMER PHYSICAL SOC2019

In situ observation of picosecond polaron self-localisation in alpha-Fe2O3 photoelectrochemical cells

Michael Graetzel, Ludmilla Steier

Hematite (alpha-Fe2O3) is the most studied artificial oxygen-evolving photo-anode and yet its efficiency limitations and their origin remain unknown. A sub-picosecond reorganisation of the hematite structure has been proposed as the mechanism which dictate ...

Springer2019

Influence of the thickness of a nanometric copper interlayer on Au/dielectric thermal boundary conductance

Ludger Weber, Maïté Blank

The influence of the thickness of a thin (1.5-30 nm) copper layer on the thermal boundary conductance (TBC) at the interface between gold and silicon, sapphire and diamond, respectively, was studied using Time Domain Thermoreflectance. Overall, a monotonic ...

2018

Temperature dependence of water-water and ion-water correlations in bulk water and electrolyte solutions probed by femtosecond elastic second harmonic scattering

Sylvie Roke, Nathan Dupertuis, Yixing Chen, Halil Ibrahim Okur

The temperature dependence of the femtosecond elastic second harmonic scattering (fs-ESHS) response of bulk light and heavy water and their electrolyte solutions is presented. We observe clear temperature dependent changes in the hydrogen (H)-bond network ...

2018

Spin dynamics from time-dependent density functional perturbation theory

Iurii Timrov

We present a new method to model spin-wave excitations in magnetic solids, based on the Liouville-Lanczos approach to time-dependent density functional perturbation theory. This method avoids computationally expensive sums over empty states and naturally d ...

EDP Sciences, Springer2018

Precision and efficiency in solid-state pseudopotential calculations

Nicola Marzari, Nicolas Frank Mounet, Antimo Marrazzo, Ivano Eligio Castelli, Gianluca Prandini

Despite the enormous success and popularity of density-functional theory, systematic verification and validation studies are still limited in number and scope. Here, we propose a protocol to test publicly available pseudopotential libraries, based on sever ...

2018

Characterization and Modeling of 28 nm Bulk CMOS Technology down to Cryogenic Temperatures (4.2 K)

Christian Enz, Farzan Jazaeri, Arnout Lodewijk M Beckers

This paper presents an experimental investigation, compact modeling, and low-temperature physics-based modeling of a commercial 28-nm bulk CMOS technology operating at cryogenic temperatures. The physical and technological parameters are extracted at 300, ...

2018

Theory and design of spherical oscillator mechanisms

Simon Nessim Henein, Roland Andreas Bitterli, Ilan Vardi, Lennart Rubbert, Mohammad Hussein Kahrobaiyan, Nicolas Ferrier, Billy Nussbaumer

In previous work, we showed that two degree of freedom oscillators can be advantageously applied to horological time bases since they can be used to eliminate the escapement mechanism. We subsequently examined planar two degree of freedom oscillators based ...

2018

The Molecular Mechanism of Nanodroplet Stability

Sylvie Roke, Evangelia Zdrali, Yixing Chen, Halil Ibrahim Okur, David Mark Wilkins

Mixtures of nano- and microscopic oil droplets in water have recently been rediscovered as miniature reaction vessels in microfluidic environments and are important constituents of many environmental systems, food, personal care, and medical products. The ...

Amer Chemical Soc2017

SmB6 electron-phonon coupling constant from time- and angle-resolved photoelectron spectroscopy

Alberto Crepaldi, Emmanouil Frantzeskakis

SmB6 is a mixed valence Kondo system resulting from the hybridization between localized f electrons and delocalized d electrons. We have investigated its out-of-equilibrium electron dynamics by means of time- and angle-resolved photoelectron spectroscopy. ...

Amer Physical Soc2016