“Berry phase and nonlinear response: photocurrent in noncentrosymmetric insulators and Weyl semimetals”
2017.08.31 11:52
장소 | #5318(E6-2. 5th fl.) |
---|---|
일시 | AUG. 31 (Thu.), 2 PM |
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., (egmoon@kaist.ac.kr)
댓글 0
번호 | 일시 | 장소 | 연사 | 제목 |
---|---|---|---|---|
공지 | 2019/09/18 - 12/5 | Seminar Room #1323 | Prof. David Schuster and etc. | Fall 2019: Physics Seminar Serises |
공지 | 2019/09/02 - 12/09 | Seminar Room 1501 | 이호성 박사 (한국표준과학연구원) and etc. | Fall 2019: Physics Colloquium |
319 | 2018년 9월 7일 (금), 3PM | 학술문화관 (E9), 2층 양승택 오디토리움 | Prof. Martin Head-Gordon, UC Berkeley |
Recent developments in density functional theory: From new functionals to the nature of the chemical bond
![]() |
318 | 5월 17일(화), 11:00 ~ 12:00 | 창의학습관(E11), 406호 | 방준혁 박사(Korea Basic Science Institute, KBSI) | The CERN Resonant WISP Search: Development, Results and Lesson-Learned |
317 | Dec. 13-14(Wed.-Thu.) 13:30 PM | 자연과학동 대형강의실 (1501호) | 장기주 교수 외 9명 |
KAIST-KIAS Joint Workshop in Theoretical Sciences 개최
![]() |
316 | August 1, 2018 at 11:00AM | 양분순 빌딩 (E16-1) 207호 | 이대열 교수, 예일대 석좌교수 |
Future of AI: Is the brain a computer?
![]() |
315 | Aug. 17(Mon), 20:00~ | Zoom webinar | Mark D. Stiles (NIST, USA) |
Using magnetic tunnel junctions to compute like the brain
![]() |
314 | Aug, 25(Tue), 20:00~ | Zoom webinar | Mark D. Stiles (NIST, USA) |
KAIST Global Forum for Spin and Beyond (Second Forum)
![]() |
313 | Sep. 14(Mon) 17:30~ | Zoom webinar | Teruo Ono (Kyoto U. Japan) |
KAIST Global Forum for Spin and Beyond (Third Forum)
![]() |
312 | Sep. 22nd 9:30 AM | Zoom webinar | Prof. Xu Yi (Univ. of Virginia, USA) |
Physics and applications of soliton microcombs(Quantum- & Nano-Photonics)
![]() |
311 | Sep.28. 5:30 pm | Zoom webinar | Burkard Hillebrands (TU Kaiserslautern, Germany) |
KAIST Global Forum for Spin and Beyond(Fourth Forum)
![]() |
310 | July 2, 2020 (Thursday) | Zoom Video Conference Seminar | Dr. Emmanuel Flurin (CEA Saclay) |
An irreversible qubit-photon coupling for the detection of itinerant microwave photons
![]() |
309 | Sep. 24(Thu), 09:00~, Sep. 24(Thu), 16:00 ~ | Zoom Video | Akash V. Dixit (University of Chicago), Dr. Boris Ivanov (Novosibirsk State Technical University) |
(CAPP/IBS)Searching for Dark Matter with a Superconducting Qubit , Cryogenic Microwave Circuit Development at the NSTU
![]() |
308 | Sep. 11(Fri), 14:00~ | zoom | 이관형교수/SNU, 이상윤교수/GIST |
SRC Seminar
![]() |
307 | December 2(Wed), 10:00AM | Zoom | Prof. Rakshya Katiwada (Illinois Institute of Technology) |
Recent progress in Axion Dark Matter eXperiment (ADMX) technology
![]() |
306 | Dec.9(Wed), 10:00AM | Zoom | Prof. Andrew Geraci (Northwestern University) |
Searching for the QCD axion with the ARIADNE experiment
![]() |
305 | Dec.10(Thu), 01:55 PM | Zoom | Yin Wen (University of Tokyo) | Consistency of Boltzmann equation and light dark matter from inflaton decay |
304 | Feb. 2(Tue) 2:30 PM | Zoom | Prof. Sangsik Kim (Texas Tech University, USA) |
Quantum- & Nano-Photonics 세미나(Integrated Nanophotonics with Metamaterials, Microcomb, and Atomic Systems)
![]() |
303 | Apr. 27, 2017 (Thu) 4:00 pm | Seminar Room(#1323, E6-2) | Prof.Donghan Lee (Chungnam National Univ.) | 반도체 양자점을 이용한 단광자 광원 |
302 | 2017/03/06 - 05/29 | Seminar Room 1501 | 이종봉 박사 (POSTECH) 외 |
Spring 2017: Physics Colloquium
![]() |
301 | 2017/03/21 - 06/08 | Seminar Room 1323 | 조길영 박사(KAIST) 외 |
Spring 2017: Physics Seminar Serises
![]() |