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Diffusive real-time dynamics of a particle with Berry curvature

Physical Review B vol.97, 075122 (2018)

2018年2月12日(月)

Kou Misaki, Seiji Miyashita, and Naoto Nagaosa ( https://doi.org/10.1103/PhysRevB.97.075122 )

Abstract

 We study theoretically the influence of Berry phase on the real-time dynamics of the singleparticle focusing on the diffusive dynamics, i.e., the time dependence of the distributionfunction. Our model can be applied to the real-time dynamics of intraband relaxation anddiffusion of optically excited excitons, trions, or particle-hole pair. We found that the dynamicsat the early stage is deeply influenced by the Berry curvature in real space (B), momentumspace (Ω), and also the crossed space between these two (C). For example, it is found that Ωinduces the rotation of the wave packet and causes the time dependence of the mean squaredisplacement of the particle to be linear in time t at the initial stage; it is qualitatively differentfrom the t3 dependence in the absence of the Berry curvature. It is also found that Ω and Cmodify the characteristic time scale of the thermal equilibration of momentum distribution.Moreover, the dynamics under various combinations of B,Ω, and C shows singular behaviorssuch as the critical slowing down or speeding up of the momentum equilibration and thereversals of the direction of rotations. The relevance of our model for time-resolvedexperiments in transition metal dichalcogenides is also discussed.

その他特記事項

The authors thank Professor P. Novak and J. Inoue for
helpful discussion and critical reading of this manuscript.
This work was supported by the Elements Strategy Initiative
Center for Magnetic Materials (ESICMM) under the
auspices of the Ministry of Education, Culture, Sports,
Science and Technology (MEXT). Some of the numerical
computations in this work were performed at the Yukawa
Institute Computer Facility and also at the Cyberscience
Center, Tohoku University.


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