Journal article
Stability, electronic quantum states, and magnetic interactions of Er3+ions in Ga2O3
Physical review materials, Vol.9(12), 126201
12/19/2025
DOI: 10.1103/z9jw-wvzd
Abstract
We report an ab initio study of phase stability, defect formation, electronic structure, and multiple magnetic, Dzyaloshinskii-Moriya, optical, hyperfine, and crystal field interactions in erbium (Er)-doped wide band gap alpha- and 9-gallium oxides (Ga2O3), critically important to make a foundation for both optoelectronic and quantum information applications. The chemical, structural, mechanical, and dynamical stabilities of the pristine phases are confirmed from respective negative formation energies, negative cohesive energies, favorable elastic constants, and positive phonon frequencies. The phonon dispersions indicate that the Ga-O bonds are uniform in the alpha-phase, while they vary in the 9-phase due to the anisotropic polyhedral movement. The defect formation energy analysis confirms that both Er-doped alpha- and 9-Ga2O3 prefer Er3+ (neutral) state. The underestimated band gaps of the pristine phases from standard density functional theory (DFT) calculations as compared to experimental values are corrected by employing the hybrid functional calculations, resulting in the indirect band gaps of 5.21 eV in alpha-Ga2O3 and 4.94 eV in 9-Ga2O3 . The site preference energy analysis indicates partial occupation of Er in the octahedral site of Ga. The anisotropic nature of hyperfine tensor coefficients of Er is similar in both phases, which may be due to the occupation of Er in the same octahedral Ga site. On the other hand, the calculated magnetic exchange interaction between two Er dopants is negative for alpha and positive for 9, indicating an antiferromagnetic (AFM) ground state in the former and a ferromagnetic (FM) ground state in the latter. Large values of Dzyaloshinskii-Moriya interactions (DMIs) are obtained along the x direction in the alpha and along the y direction in the 9. The large DMI may support exotic magnetic textures, a promising direction for spintronic applications. The analysis of dielectric constants and refractive indices of both pristine and Er-doped phases shows a good agreement with available experimental values. The calculated optical anisotropy is slightly higher in 9 than those in alpha, which is due to the involvement of lower symmetry in 9. The crystal field coefficients (CFCs) calculated from DFT are used to analyze 4 f multiplets and 4 f-4 f transitions. Thus calculated lowest energy level of the first excited state to the lowest energy level of the ground state is about 1.53 mu m, which is in a good agreement with available experiments, and it falls within the quantum telecommunication wavelength range.
Details
- Title: Subtitle
- Stability, electronic quantum states, and magnetic interactions of Er3+ions in Ga2O3
- Creators
- Yogendra Limbu - University of IowaHari Paudyal - University of IowaMichael E. Flatte - University of IowaDurga Paudyal - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Physical review materials, Vol.9(12), 126201
- DOI
- 10.1103/z9jw-wvzd
- ISSN
- 2475-9953
- Publisher
- Amer Physical Soc
- Number of pages
- 11
- Grant note
- DMR23051 / Argon highperformance computing system at the University of Iowa
- Language
- English
- Date published
- 12/19/2025
- Academic Unit
- Electrical and Computer Engineering; Physics and Astronomy
- Record Identifier
- 9985116067402771
Metrics
1 Record Views