“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 |
236 | 2015/06/03, 12PM | Room 101, E11 | Prof. Min-Kyo, Seo & Hansuek, Lee(KAIST) |
The First Wednesday Multidisciplinary Forum
![]() |
235 | Nov. 10th(Thu) 4 p.m. | E6-2. #1323(1st fl.) | Prof. Min Seok Jang, Electrical Engineering, KAIST | Low Dimensional Active Plasmonics and Electron Optics in Graphene |
234 | 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
![]() |
233 | Apr. 19(Tue.), 2PM | #1323(E6-2. 1st fl.) | Prof. Mark Koepke, Department of Physics and Astronomy, West Virginia University, USA | Nonlocal collisional electron transport in partially ionized plasma generation, structure, and stability |
232 | November 28 (Thu.), 16:00 PM | #1323, E6-2 | Prof. Kyung Taec Kim |
Generation of coherent EUV emissions using ultrashort laser pulses
![]() |
231 | May 9 (Thu.), 16:00 PM | #1323, E6-2 | Prof. Kwang Geol Lee |
Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters
![]() |
230 | May 9 (Thu.), 16:00 PM | #1323, E6-2 | Prof. Kwang Geol Lee |
Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters
![]() |
229 | February 12(Web.) | E6-2, #5318 | Prof. Kunio Kaneta |
From inflation to new weak-scale
![]() |
228 | October 24 (Wed.), 10:30 AM | E6-1, Lecture Room 1501(1F) | Prof. Kerry J. Vahala |
Photonic integration of next-generation clocks and Hertz-absolute-accuarcy optical frequenncy synthesizers
![]() |
227 | June 14 (THU), 10:00 AM | E6-2, 2nd fl. #2502 | Prof. Kenji Toyoda |
Phonons and polariton-like particles in trapped ions for quantum computation and quantum simulation
![]() |
226 | DEC. 16~18 (Sun~Tue) | E6-2. 1st fl. #1323 | Prof. Keisuke Totsuka |
Lectures on 2d Conformal Field Theory
![]() |
225 | MAR. 26 (TUE), 0300 PM | E6-2. 2st fl. #2501 | Prof. Jung Hoon Han |
Consideration of thermal Hall effect in frustrated and un-frustrated quantum magnets
![]() |
224 | October 11 (Thu.), 16:00 PM | #1323, E6-2 | Prof. Joung-Real Ahn |
Dirac electrons in a graphene quasicrystal
![]() |
223 | October 29 (Tue.), 14:30 PM | #1323, E6-2 | Prof. Jörg Wrachtrup |
Quantum sensing
![]() |
222 | May 2 (Thu.), 4:00 PM | #1323, E6-2 | Prof. Joon Ik Jang |
Anomalous optical properties of halide perovskites
![]() |
221 | April 11 (Thu.), 16:00 PM | #1323, E6-2 | Prof. Joo-Hyoung Lee, GIST |
Massive screening for cathode active materials using deep neural network
![]() |
220 | September 20 (Thu.), 16:00 | #1323, E6-2 | Prof. Joo-Hiuk Son |
Toward Cancer Treatment Using Terahertz Radiation: Demethylation of Cancer DNA
![]() |
219 | October 18 (Thu.), 16:00 PM | #1323, E6-2 | Prof. Jongseok Lee |
Applications of nonlinear optics for condensed matter researches
![]() |
218 | May 9 (Wed.), 04:00 PM | #1323, E6-2 | Prof. Jong-Soo Rhyee |
Recent advances in thermoelectric bulk composites
![]() |
217 | 2017.1.9(Mon), 4PM | Lecture Hall, College of Natural Sciences [#1501,E6-2] | Prof. John Michael Kosterlitz, Brown University |
Topological Defects and Phase Transitions"
![]() |