Ab initio calculations of the crystal field and phonon dispersions in CePd2Al2 and LaPd2Al2

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F20%3A10411126" target="_blank" >RIV/00216208:11320/20:10411126 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61989100:27640/20:10244870 RIV/61989100:27740/20:10244870

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=MgWtNP7oKb" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=MgWtNP7oKb</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1361-648X/ab7031" target="_blank" >10.1088/1361-648X/ab7031</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Ab initio calculations of the crystal field and phonon dispersions in CePd2Al2 and LaPd2Al2

Popis výsledku v původním jazyce

CePd2Al2 crystallizes in the CaBe2Ge2-type tetragonal structure (P4/nmm, 129) and undergoes a phase transition to the orthorhombic Cmme structure at around 13 K. Its inelastic neutron spectra reveal an additional magnetic excitation that was ascribed to electron-phonon interaction leading to a formation of a new quantum quasi-bound vibron state. We present the first-principles calculations of the crystal field excitations and lattice dynamics calculations of the phonon dispersions to compare with the experimental data. The calculated crystal field energy splitting in CePd2Al2 agrees well with the model used to describe the experimental neutron scattering spectra. The first excited crystal field level moves to higher energies when undergoing the transformation from tetragonal to orthorhombic structure, in agreement with the experiment. The analysis based on calculated elastic constants and lattice dynamics calculations show that in both tetragonal and orthorhombic structures there are no imaginary modes for any q-wave vector within the Brillouin zone, and therefore the lattice structures are stable. The phonon dispersions and density of states are calculated for both crystal structures of CePd2Al2 and its nonmagnetic counterpart LaPd2Al2. The results generally agree well with the experimental data including the high phonon density of states around 12 meV. The phonon density of states is also used to calculate the mean squared displacement, Debye temperature, lattice heat capacity and compared with similar properties of the available experiment.

Název v anglickém jazyce

Ab initio calculations of the crystal field and phonon dispersions in CePd2Al2 and LaPd2Al2

Popis výsledku anglicky

CePd2Al2 crystallizes in the CaBe2Ge2-type tetragonal structure (P4/nmm, 129) and undergoes a phase transition to the orthorhombic Cmme structure at around 13 K. Its inelastic neutron spectra reveal an additional magnetic excitation that was ascribed to electron-phonon interaction leading to a formation of a new quantum quasi-bound vibron state. We present the first-principles calculations of the crystal field excitations and lattice dynamics calculations of the phonon dispersions to compare with the experimental data. The calculated crystal field energy splitting in CePd2Al2 agrees well with the model used to describe the experimental neutron scattering spectra. The first excited crystal field level moves to higher energies when undergoing the transformation from tetragonal to orthorhombic structure, in agreement with the experiment. The analysis based on calculated elastic constants and lattice dynamics calculations show that in both tetragonal and orthorhombic structures there are no imaginary modes for any q-wave vector within the Brillouin zone, and therefore the lattice structures are stable. The phonon dispersions and density of states are calculated for both crystal structures of CePd2Al2 and its nonmagnetic counterpart LaPd2Al2. The results generally agree well with the experimental data including the high phonon density of states around 12 meV. The phonon density of states is also used to calculate the mean squared displacement, Debye temperature, lattice heat capacity and compared with similar properties of the available experiment.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Physics Condensed Matter

ISSN

0953-8984

e-ISSN

—

Svazek periodika

32

Číslo periodika v rámci svazku

23

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

9

Strana od-do

235402

Kód UT WoS článku

000520462000001

EID výsledku v databázi Scopus

2-s2.0-85083117606