TY - JOUR
T1 - High Curie temperature in Eu-doped GaN caused by volume-compensated Ga-vacancy
AU - Masago, Akira
AU - Shinya, Hikari
AU - Fukushima, Tetsuya
AU - Sato, Kazunori
AU - Katayama-Yoshida, Hiroshi
N1 - Funding Information:
This work was partly supported by JST CREST (Grant Nos. JPMJCR1777 and JPMJCR18I2) and JSPS KAKENHI (Grant Nos. 18K04926 and 18H05212). The computation was done at the Supercomputer Center, ISSP, University of Tokyo. T.F. thanks “Building of Consortia for the Development of Human Resources in Science and Technology.”
PY - 2020/2/1
Y1 - 2020/2/1
N2 - This study computationally demonstrates that room-temperature ferromagnetism, which has been experimentally observed in Eu-doped GaN, is induced by holes in N 2p states (i.e., Zener's double exchange interaction) that arise on the assumption that Ga vacancies appear as a result of the introduction of Eu ions (i.e., volume compensation). The calculated Curie temperature (TC) suddenly increases over a certain range of Ga-vacancy concentrations and gradually increases with an increasing concentration of Eu ions. High TC above room temperature is dominated by Zener's double exchange mechanism in partially occupied N 2p hole-states, which itinerate throughout the whole crystals, and low TC is dominated by Zener's p-f exchange mechanism in Eu 4f and N 2p hybridization. We can reasonably explain the surprising experimental data of 4000 μB per Gd atom in Gd-doped GaN reported by Dhar et al. [Phys. Rev. Lett. 94, 037205 (2005)].
AB - This study computationally demonstrates that room-temperature ferromagnetism, which has been experimentally observed in Eu-doped GaN, is induced by holes in N 2p states (i.e., Zener's double exchange interaction) that arise on the assumption that Ga vacancies appear as a result of the introduction of Eu ions (i.e., volume compensation). The calculated Curie temperature (TC) suddenly increases over a certain range of Ga-vacancy concentrations and gradually increases with an increasing concentration of Eu ions. High TC above room temperature is dominated by Zener's double exchange mechanism in partially occupied N 2p hole-states, which itinerate throughout the whole crystals, and low TC is dominated by Zener's p-f exchange mechanism in Eu 4f and N 2p hybridization. We can reasonably explain the surprising experimental data of 4000 μB per Gd atom in Gd-doped GaN reported by Dhar et al. [Phys. Rev. Lett. 94, 037205 (2005)].
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U2 - 10.1063/1.5116054
DO - 10.1063/1.5116054
M3 - Article
AN - SCOPUS:85079677798
VL - 10
JO - AIP Advances
JF - AIP Advances
SN - 2158-3226
IS - 2
M1 - 025216
ER -