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Infrared dielectric functions and Brillouin zone center phonons of

Stokey, Megan ; Korlacki, Rafał ; Hilfiker, Matthew ; Knight, Sean ; Richter, Steffen LU ; Darakchieva, Vanya LU ; Jinno, Riena ; Cho, Yongjin ; Xing, Huili Grace and Jena, Debdeep , et al. (2022) In Physical Review Materials 6(1).
Abstract

We determine the anisotropic dielectric functions of rhombohedral α-Ga2O3 by far-infrared and infrared generalized spectroscopic ellipsometry and derive all transverse optical and longitudinal optical phonon mode frequencies and broadening parameters. We also determine the high-frequency and static dielectric constants. We perform density functional theory computations and determine the phonon dispersion for all branches in the Brillouin zone, and we derive all phonon mode parameters at the Brillouin zone center including Raman-active, infrared-active, and silent modes. Excellent agreement is obtained between our experimental and computation results as well as among all previously reported partial information from experiment and theory.... (More)

We determine the anisotropic dielectric functions of rhombohedral α-Ga2O3 by far-infrared and infrared generalized spectroscopic ellipsometry and derive all transverse optical and longitudinal optical phonon mode frequencies and broadening parameters. We also determine the high-frequency and static dielectric constants. We perform density functional theory computations and determine the phonon dispersion for all branches in the Brillouin zone, and we derive all phonon mode parameters at the Brillouin zone center including Raman-active, infrared-active, and silent modes. Excellent agreement is obtained between our experimental and computation results as well as among all previously reported partial information from experiment and theory. We also compute the same information for α-Al2O3, the binary parent compound for the emerging alloy of α-(AlxGa1−x)2O3, and use results from previous investigations [Schubert, Tiwald, and Herzinger, Phys. Rev. B 61, 8187 (2000)10.1103/PhysRevB.61.8187] to compare all properties among the two isostructural compounds. From both experimental and theoretical investigations, we compute the frequency shifts of all modes between the two compounds. Additionally, we calculate overlap parameters between phonon mode eigenvectors and discuss the possible evolution of all phonon modes into the ternary alloy system and whether modes may form single-mode or more complex mode behaviors.

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publishing date
type
Contribution to journal
publication status
published
in
Physical Review Materials
volume
6
issue
1
article number
014601
publisher
American Physical Society
external identifiers
  • scopus:85122851669
ISSN
2475-9953
DOI
10.1103/PhysRevMaterials.6.014601
language
English
LU publication?
no
additional info
Publisher Copyright: © 2022 American Physical Society
id
6702afc3-8659-4578-a932-5fc26a79e32f
date added to LUP
2022-04-19 14:39:17
date last changed
2022-07-06 15:22:50
@article{6702afc3-8659-4578-a932-5fc26a79e32f,
  abstract     = {{<p>We determine the anisotropic dielectric functions of rhombohedral α-Ga2O3 by far-infrared and infrared generalized spectroscopic ellipsometry and derive all transverse optical and longitudinal optical phonon mode frequencies and broadening parameters. We also determine the high-frequency and static dielectric constants. We perform density functional theory computations and determine the phonon dispersion for all branches in the Brillouin zone, and we derive all phonon mode parameters at the Brillouin zone center including Raman-active, infrared-active, and silent modes. Excellent agreement is obtained between our experimental and computation results as well as among all previously reported partial information from experiment and theory. We also compute the same information for α-Al2O3, the binary parent compound for the emerging alloy of α-(AlxGa1−x)2O3, and use results from previous investigations [Schubert, Tiwald, and Herzinger, Phys. Rev. B 61, 8187 (2000)10.1103/PhysRevB.61.8187] to compare all properties among the two isostructural compounds. From both experimental and theoretical investigations, we compute the frequency shifts of all modes between the two compounds. Additionally, we calculate overlap parameters between phonon mode eigenvectors and discuss the possible evolution of all phonon modes into the ternary alloy system and whether modes may form single-mode or more complex mode behaviors.</p>}},
  author       = {{Stokey, Megan and Korlacki, Rafał and Hilfiker, Matthew and Knight, Sean and Richter, Steffen and Darakchieva, Vanya and Jinno, Riena and Cho, Yongjin and Xing, Huili Grace and Jena, Debdeep and Oshima, Yuichi and Khan, Kamruzzaman and Ahmadi, Elaheh and Schubert, Mathias}},
  issn         = {{2475-9953}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review Materials}},
  title        = {{Infrared dielectric functions and Brillouin zone center phonons of}},
  url          = {{http://dx.doi.org/10.1103/PhysRevMaterials.6.014601}},
  doi          = {{10.1103/PhysRevMaterials.6.014601}},
  volume       = {{6}},
  year         = {{2022}},
}