“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 |
---|---|---|---|---|
152 | Dec. 13-14(Wed.-Thu.) 13:30 PM | 자연과학동 대형강의실 (1501호) | 장기주 교수 외 9명 |
KAIST-KIAS Joint Workshop in Theoretical Sciences 개최
![]() |
151 | Dec. 12th (Mon) | 1:30p.m. #1323(E6-2. 1st fl.) | Dongjoon Song , AIST | “Possible symmetry in the phase diagrams of electron- & hole-doped cuprate high-Tc superconductors” |
150 | DEC. 11 (Tue), 04:00 PM | E6-2. 1st fl. #1323 | Prof. Hiroshi Shinaoka |
Natural compact representation of Matsubara Green’s functions: applications to analytic continuation and quantum many-body simulations
![]() |
149 | Dec. 11 (Fri.), 04:00 PM | online | Hyobin Yoo(Sogang Univ.) | Atomic and electronic reconstruction at van der Waals interface in twisted 2D materials |
148 | Dec. 11 (Fri.), 02:30 PM | online | Myung Hwa Jung(Sogang Univ.) | Antisymmetric interlayer exchange coupling in magnetic multilayers |
147 | Dec 27 (Fri), 3:00 PM | #5318, E6-2 | Han Gyeol Suh |
The superconducting order parameter puzzle of Sr2RuO4
![]() |
146 | August. 6th (TUE), 14:00 | E6 Room(#1323) | Kanghyun Chu |
Visualization of in-plane piezoresponse vector fields
![]() |
145 | August. 1st (Thu), 14:00 | E6 Room(#1323) | Hyeok Yoon |
Low-density Superconductivity in SrTiO3 Probed by Planar Tunneling Spectroscopy
![]() |
144 | August. 16th (Fri), 14:00 | E6 Room(#1323) | Jinxing Zhang |
Multiferroic and Magnetoelectric Effects by Tailoring Interfacial Chemistry and Physics in Correlated Oxides
![]() |
143 | August. 14th (Wed.), 4:00PM, | Rm. 1323, E6 | Prof. Nicolas Treps |
Quantum Optics, at the heart of quantum metrology and quantum information
![]() |
142 | August 27 (Tue.), 4:00PM | Rm. 1323, E6 | Hiroshi Eisaki |
Critical current properties of Fe-based superconductors
![]() |
141 | August 1, 2018 at 11:00AM | 양분순 빌딩 (E16-1) 207호 | 이대열 교수, 예일대 석좌교수 |
Future of AI: Is the brain a computer?
![]() |
140 | Aug. 4, 2016 (Thu.), 2:30 pm | KAIST Natural Science Building (E6-5), EDU 3.0 Room(1st fl.) | Prof. Argyris Nicolaidis | Relational Logic (with applications to Quantum Mechanics, String Theory, Cosmology, Neutrino Oscillations, Statistical Mechanics) |
» | AUG. 31 (Thu.), 2 PM | #5318(E6-2. 5th fl.) | Prof. Hiroaki Ishizuka (The University of Tokyo) |
“Berry phase and nonlinear response: photocurrent in noncentrosymmetric insulators and Weyl semimetals”
![]() |
138 | Aug. 17(Mon), 20:00~ | Zoom webinar | Mark D. Stiles (NIST, USA) |
Using magnetic tunnel junctions to compute like the brain
![]() |
137 | Aug. 16 (Wed.), 4 PM | #1322 (E6-2. 1st fl.) | Prof. Noejung Park (UNIST) |
Phonon-driven spin-Floquet valleytro-magnetism
![]() |
136 | Aug, 25(Tue), 20:00~ | Zoom webinar | Mark D. Stiles (NIST, USA) |
KAIST Global Forum for Spin and Beyond (Second Forum)
![]() |
135 | April 6, 2017 (Thu), 4:00 pm | IBS CAPP seminar room, Creation Hall (3F), KAIST Munji Campus | Prof. Youngjoon Kwon (Yonsei University) | For whom the Belle tolls |
134 | April 6, 2016 (Wed), 3:30 PM | E6-2, RM #1323 | Dr. Andrei Matlashov (Los Alamos National Laboratory) | Superconducting Quantum Interference Devices for Precision Detection |
133 | April 6 (Fri.), 10:00 AM | #2502, E6 | 박채연 박사 |
Entanglement and thermalization in many-body systems: recent progress
![]() |