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Naslov:Infrared spectra in amorphous alumina : a combined ab initio and experimental study
Avtorji:ID Giacomazzi, Luigi (Avtor)
ID Shcheblanov, Nikita S. (Avtor)
ID Povarnitsyn, Mikhail E. (Avtor)
ID Li, Yanbo (Avtor)
ID Mavrič, Andraž (Avtor)
ID Zupančič, Barbara (Avtor)
ID Grdadolnik, Jože (Avtor)
ID Pasquarello, Alfredo (Avtor)
Datoteke:URL https://arxiv.org/abs/2304.14090
 
URL https://journals.aps.org/prmaterials/abstract/10.1103/PhysRevMaterials.7.045604
 
Jezik:Angleški jezik
Vrsta gradiva:Neznano
Tipologija:1.01 - Izvirni znanstveni članek
Organizacija:UNG - Univerza v Novi Gorici
Opis:We present a combined study based on the experimental measurements of an infrared (IR) dielectric function and first-principles calculations of IR spectra and the vibrational density of states (VDOS) of amorphous alumina (am−Al2O3). In particular, we show that the main features of the imaginary part of the dielectric function ε2(ω) at ∼380 and 630 cm−1 are related to the motions of threefold-coordinated oxygen atoms, which are the vast majority of oxygen atoms in am-Al2O3. Our analysis provides an alternative point of view with respect to an earlier suggested assignment of the vibrational modes, which relates them to the stretching and bending vibrational modes of AlOn (n=4, 5, and 6) polyhedra. Our assignment is based on the additive decomposition of the VDOS and ε2(ω) spectra, which shows that (i) the band at ∼380cm−1 features oxygen motions occurring in a direction normal to the plane defined by the three nearest-neighbor aluminum atoms, i.e., out-of-plane motions of oxygen atoms; (ii) Al-O stretching vibrations (i.e., in-plane motions of oxygen atoms) appear at frequencies above ∼500cm−1, which characterize the vibrational modes underlying the band at ∼630cm−1. Aluminum and fourfold-coordinated oxygen atoms contribute uniformly to the VDOS and ε2(ω) spectra in the frequency region ∼350–650 cm−1 without causing specific features. Our numerical results are in good agreement with the previous and presently obtained experimental data on the IR dielectric function of am−Al2O3 films. Finally, we show that the IR spectrum can be modeled successfully by assuming isotropic Born charges for aluminum atoms and fourfold-coordinated oxygen atoms, while requiring the use of three parameters, defined in a local reference frame, for the anisotropic Born charges of threefold-coordinated oxygen atoms.
Ključne besede:dielectric properties, microstructure, amorphous materials, density functional calculations, infrared techniques, aluminium oxide
Datum objave:01.04.2023
Leto izida:2023
Št. strani:str. 045604-1-045604-14
Številčenje:Vol. 7, iss. 4
PID:20.500.12556/RUNG-8171-915083a3-008c-b01c-ceb6-e6661911db23 Novo okno
COBISS.SI-ID:150364419 Novo okno
UDK:53
ISSN pri članku:2475-9953
DOI:10.1103/PhysRevMaterials.7.045604 Novo okno
NUK URN:URN:SI:UNG:REP:G8HEHID0
arXiv:2304.14090 Novo okno
Datum objave v RUNG:10.05.2023
Število ogledov:1415
Število prenosov:7
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Gradivo je del revije

Naslov:Physical review materials
Založnik:American Physical Society
ISSN:2475-9953
COBISS.SI-ID:31354663 Novo okno

Gradivo je financirano iz projekta

Financer:ARRS - Agencija za raziskovalno dejavnost Republike Slovenije
Številka projekta:P2-0412
Naslov:Heterogeni procesi na površinah trdnin za trajnostne tehnologije

Financer:ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
Številka projekta:NC-0018
Naslov:Deskriptor za atomsko strukturo induciranih pozicijskih napak v polprevodnikih

Financer:ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
Številka projekta:J2-2498
Naslov:Redukcija ogljikovega dioksida na katalizatorju z izoliranimi atomi za tvorbo spojin z dodano vrednostjo

Licence

Licenca:CC BY-NC-ND 4.0, Creative Commons Priznanje avtorstva-Nekomercialno-Brez predelav 4.0 Mednarodna
Povezava:http://creativecommons.org/licenses/by-nc-nd/4.0/deed.sl
Opis:Najbolj omejujoča licenca Creative Commons. Uporabniki lahko prenesejo in delijo delo v nekomercialne namene in ga ne smejo uporabiti za nobene druge namene.
Začetek licenciranja:25.04.2023

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