• HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2017-08-31 14:00 
일시 AUG. 31 (Thu.), 2 PM 
장소 #5318(E6-2. 5th fl.) 
연사 Prof. Hiroaki Ishizuka (The University of Tokyo) 

“Berry phase and nonlinear response: photocurrent in noncentrosymmetric insulators and Weyl semimetals”

Prof. Hiroaki Ishizuka (The University of Tokyo)

AUG. 31 (Thu.), 2 PM / #5318(E6-2. 5th fl.)


Berry phase is one of the important keywords to understand non-trivial quantum effects. In condensed matter physics, the Berry phase often shows up in transport phenomena (e.g., quantum and anomalous Hall effects) and is considered as a keyword to understand topological properties of non-interacting fermion systems. While most of such studies have focused on the equilibrium states or linear responses in close to the equilibrium, a recent study on the photogalvanic effects have pointed out the relation between the Berry phase and photogalvanic effects in noncentrosymmetric insulators where inter-band transitions take an essential role [1-3]; it is named shift current as it is related to the shift of the Wannier function. So far, however, no observable consequences that distinguish this phenomenon from the conventional mechanism is known. In this talk, we theoretically explored the basic properties of shift current focusing on the distinction between the conventional and shift current mechanisms. 

To theoretically study the photocurrent, we employed a Keldysh Green’s function formalism combined with Floquet theory. Using a large size numerical calculation, we study how the photocurrent changes by the local excitation, i.e., when only a part of the system is irradiated by the light. We show that, for the shift current, the magnitude of the current does not depend on the position of the light [4]. This is in contrast to the conventional mechanism, where the photocurrent is expected to be larger at the edge of the sample while it is suppressed when the light is at the center. Such behavior is consistent with the photocurrent recently observed in a noncentrosymmetric organic solid [5].

In the latter half of the talk, we discuss the effect of Berry phase on the photocurrent in Weyl semimetals [6,7]. We show that the Berry phase associated with the Weyl nodes induce a similar phenomenon to the adiabatic pump, resulting in a dissipation-less photocurrent. We find that the photocurrent appears only with the circularly polarized lights. This mechanism may potentially explain the photocurrent observed in TaAs [8].


[1] W. Kraut and R. von Blatz, Phys. Rev. B 19, 1548 (1979); ibid. 23, 5590 (1981). 

[2] J. E. Sipe and A. I. Shkrebtii, Phys. Rev. B 61, 5337 (2000).

[3] T. Morimoto and N. Nagaosa, Science Adv. 2, e1501524 (2016).

[4] H. Ishizuka and N. Nagaosa, New J. Phys. 19, 033015 (2017).

[5] M. Nakamura, et al., Nature Commun. 8, 281 (2017).

[6] H. Ishizuka et al., Phys. Rev. Lett. 117, 216601 (2016).

[7] H. Ishizuka et al., Phys. Rev. B 95, 245211 (2017).

[8] Q. Ma et al., preprint (arXiv: 1705.00690).


Contact: Eun Gook Moon, Physics Dept., (

20170831_Hiroaki Ishizuka.pdf

번호 날짜 장소 제목
384 2018-12-27 16:00  E6-2. 1st fl. #1323  Quantum Innovation (QuIN) Laboratory file
383 2023-09-27 16:00  E6, Rm#2501  Chiral Magnets: Domain-Wall Skyrmions and String Theory Realization
382 2019-06-04 17:00  #1323, E6-2  Stochastic nature of bacterial eradication using antibiotics file
381 2015-06-03 12:00  Room 101, E11  The First Wednesday Multidisciplinary Forum file
380 2016-11-10 16:00  E6-2. #1323(1st fl.)  Low Dimensional Active Plasmonics and Electron Optics in Graphene
379 2023-07-20 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP Seminar] Cosmoparticle Physics of Dark Universe file
378 2018-09-07 15:00  학술문화관 (E9), 2층 양승택 오디토리움  Recent developments in density functional theory: From new functionals to the nature of the chemical bond file
377 2021-04-09 10:00  Zoom webinar  Integrated Lithium Niobate Photonics file
376 2016-04-19 14:00  #1323(E6-2. 1st fl.)  Nonlocal collisional electron transport in partially ionized plasma generation, structure, and stability
375 2023-08-24 11:00  E6, Rm#1323  Advancing magnonic metamaterials: spin waves in nanomagnetic arrays
374 2024-05-28 10:00  E6-2, #2501  Mixed-State Quantum Spin Liquids and Dynamical Anyon Condensations in Kitaev Lindbladians
373 2019-11-28 16:00  #1323, E6-2  Generation of coherent EUV emissions using ultrashort laser pulses file
372 2022-05-20 11:00  E6-1 #1323  (응집물리 세미나) Exploration of new polymorphs in van der Waals crystals
371 2019-05-09 16:00  #1323, E6-2  Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters file
370 2019-05-09 16:00  #1323, E6-2  Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters file
369 2020-02-12 13:00  E6-2, #5318  From inflation to new weak-scale file
368 2018-10-24 10:30  E6-1, Lecture Room 1501(1F)  Photonic integration of next-generation clocks and Hertz-absolute-accuarcy optical frequenncy synthesizers file
367 2018-06-14 10:00  E6-2, 2nd fl. #2502  Phonons and polariton-like particles in trapped ions for quantum computation and quantum simulation file
366 2018-12-16 16:00  E6-2. 1st fl. #1323  Lectures on 2d Conformal Field Theory file
365 2023-11-22 16:00  E6-2, #2502  [High Energy Theory Seminar] Renormalization and the Hierarchy Problem