“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 |
159 | 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
![]() |
158 | July 13, 2018 at 14:00 | Room 5318, KAIST Natural Sciences Lecture Hall(E6). | Prof. Ian Lewis (The University of Kansas, Department of Physics & Astronomy) | Loop Induced Single Top Partner Production and Decay at the LHC |
157 | July 10 (Wed.), 04:00 PM- | Academic Cltural Complex (E9) 5층 스카이라운지 | Prof. Sidney Nagel/Young-Kee Kim |
Public Lectures
![]() |
156 | Jul. 28 (Thu.) 4PM | #1323(E6-2. 1st fl.) | Prof. Johannes Pollanen, Jerry Cowen Chair of Experimental Physics at Michigan State University | Low Dimensional Electrons: On the Road to Hybrid Quantum Systems |
155 | Jul. 08 (Fri.) 2PM | #1323(E6-2. 1st fl.) | Dr. Junhyun Lee, Harvard University | Electronic quasiparticles in the quantum dimer model |
154 | Jul. 08 (Fri.) 11:00 AM | #1323(E6-2. 1st fl.) | Dr. Michael Lawler(Binghampton Univ. / Cornell Univ.) | Isostatic magnetism |
153 | Jul. 07 (Thu.) 2PM | #1323(E6-2. 1st fl.) | Dr. Eun Ah Kim, CORNELL UNIV. | Let there be topological superconductors |
152 | Jul 3rd, 2019 (Wed) | E6-2, 2501 | Kyung Soo Choi |
Many-body quantum electrodynamis (QED) with atoms and photons: A new platform for quantum optics"
![]() |
151 | January 23, 2019 | Rm. C303, Creation Hall (3F), Munji Campus | Mikko Mottonen |
Ultrasensitive Microwave Bolometer: Opportunity for Axion Detectors
![]() |
150 | January 17 (Fri), 4:00 PM | #1323, E6-2 | Hiroki Ikegami |
Symmetry Breaking and Topology in Superfluid 3He
![]() |
149 | Jan.9 (Wed.), 04:00 PM | E6-2. 2nd fl. #2501 | Dr. Heung-Sik Kim |
Molecular Mott state in the deficient spinel GaV4S8
![]() |
148 | JAN. 7 (Mon), 03:00 PM | E6-2. 2st fl. #2501 | Dr. Byoung min Kang |
Many-Body Invariants for Multipoles in Higher-Order Topological Insulators
![]() |
147 | February 21 (Thu.), 16:00 PM | #5313, E6-2 | Prof. Diptimoy Ghosh |
B-meson charged current anomalies - Theoretical status
![]() |
146 | February 20 (Thu), 4:00 PM | #1323, E6-2 | Seunghyun Khim |
Unconventional superconductivity in the locally non-centrosymmetric heavy-fermion CeRh2As2
![]() |
145 | February 13th (Thur.), 16:30 PM | E6-6, #119 | Dr. Seyoon Kim(University of Wisconsin-Madison) |
Enhanced Light-Matter Interactions in Graphene with Noble Metal Plasmonic Structures
![]() |
144 | February 12(Web.) | E6-2, #5318 | Prof. Kunio Kaneta |
From inflation to new weak-scale
![]() |
143 | Feb. 25 - Jun 3 | Rm. 1501 (E6) |
Spring 2019: Physics Colloquium
![]() | |
142 | Feb. 12 (Mon), 3:00pm | #C303, (Creation Hall 3F, KAIST Munji Campus) | Dr. Byeongsu Yang, Kamioka Observatory, Univ. of Tokyo | The recent result of XMASS Experiment |
141 | Feb. 1 (Wed.), 2p.m. | #1323(E6-2. 1st fl.) | Dr. Michihisa Yamamoto, Department of Applied Physics, The University of Tokyo | Quantum electron optics using flying electrons |
140 | December 5 (Thu.), 16:00 PM | #1323, E6-2 | Prof. Soon-Hong Kwon |
Subwavelenth Photonic Devices: From Single Photon Sources to Solar Cell
![]() |