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Synergetic effect of spin-orbit coupling and Zeeman splitting on the optical conductivity in theone-dimensional Hubbard model

Phys. Rev. B 95, 235115 (2017)

2017年6月8日(木)

Adrien Bolens, Hosho Katsura, Masao Ogata, and Seiji Miyashita ( https://doi.org/10.1103/PhysRevB.95.235115 )

Abstract

We study how the synergetic effect of spin-orbit coupling (SOC) and Zeeman splitting (ZS)affects the optical conductivity in the one-dimensional Hubbard model using the Kubo formula.We focus on two phenomena: (1) the electric dipole spin resonance (EDSR) in the metallicregime and (2) the optical conductivity in the Mott-insulating phase above the optical gap. Inboth cases, we calculate qualitatively the effects of SOC and ZS and how they depend on therelative angle between the SOC vector and the magnetic field direction. First, we investigatethe spin resonance without electron correlation (the Hubbard parameter U=0). Although,neither SOC nor ZS causes any resonance by itself in the optical conductivity, the EDSRbecomes possible when both of them exist. The resulting contribution to the opticalconductivity is analyzed analytically. The effect of U on the spin resonance is also studied witha numerical method. It is found that at half filling, the resonance is first enhanced for small Uand then suppressed when the optical gap is large enough. In the strong coupling limit U→∞ athalf filling, we also refer to the resonance between the lower and upper Hubbard bandsappearing at ω∼U, above the optical gap. A large magnetic field tends to suppress the signalwhile it is recovered thanks to SOC depending on the relative angle of the magnetic field.

その他特記事項

The authors thank Oleg Starykh for bringing our attention to Refs. [34,35]. A.B. acknowledges FMSPfor the encouragement of the present study. H.K. was supported in part by JSPS KAKENHI GrantsNo.JP15K17719 and No. JP16H00985.The present work was supported by the Elements StrategyInitiative Center for Magnetic Materials (ESICMM) under the outsourcing project of MEXT. Thenumerical calculations were supported by the supercomputer center of the Institute for Solid StatePhysics of the University of Tokyo.


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元素戦略プロジェクト(活動紹介)
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元素戦略拠点

触媒・電池元素戦略拠点
触媒・電池元素戦略研究拠点 (京都大学)
東工大元素戦略拠点
東工大元素戦略拠点 (東京工業大学)
構造材料元素戦略研究拠点
構造材料元素戦略研究拠点 (京都大学)
高効率モーター用磁性材料技術研究組合
高効率モーター用 磁性材料技術研究組合