logo

korean english

게시판

Home > 게시판 > 세미나

다음과 같이 세미나 모임을 개최합니다. 많은 참석 부탁합니다. 참석자에게는 점심을 제공합니다.


 2015/ 4/ 25/ 토/


연사: 박두선 교수 (성균관대)

시간: 오전 10:30-12:00

장소: 삼성학술정보관 7층 Creative Learning Room

제목: Controlling superconductivity by tunable quantum critical points

초록:The heavy fermion compound CeRhIn5 is a rare example where a quantum critical point, hidden by a dome of superconductivity, has been explicitly revealed and found to have a local nature. The lack of additional examples of local types of quantum critical points associated with superconductivity, however, has made it difficult to unravel the role of quantum fluctuations in forming Cooper pairs. Here, we show the precise control of superconductivity by tunable quantum critical points in CeRhIn5. Slight tin-substitution for indium in CeRhIn5 shifts its antiferromagnetic quantum critical point from 2.3 GPa to 1.3 GPa and induces a residual impurity scattering 300 times larger than that of pure CeRhIn5, which should be sufficient to preclude superconductivity. Nevertheless, superconductivity occurs at the quantum critical point of the tin-doped metal. These results underline that fluctuations from the antiferromagnetic quantum criticality promote unconventional superconductivity in CeRhIn5.


연사: 김기석 교수 (포항공대)

시간: 오후 1:00-4:00

장소: 물리학과 라운지 세미나실 (31동 2층)

제목: Emergent gauge fields and their nonperturbative effects in correlated electrons

초록: The history of modern condensed matter physics may be regarded as the competition and reconciliation between Stoner's and Anderson's physical pictures, where the former is based on momentum-space descriptions focusing on long wave-length fluctuations while the latter is based on real-space physics emphasizing emergent localized excitations. In particular, these two view points compete with each other in various nonperturbative phenomena, which range from the problem of high Tc superconductivity, quantum spin liquids in organic materials and frustrated spin systems, heavy-fermion quantum criticality, metal-insulator transitions in correlated electron systems such as doped silicons and two-dimensional electron systems, the fractional quantum Hall effect, to the recently discussed Fe-based superconductors. An approach to reconcile these competing frameworks is to introduce topologically nontrivial excitations into the Stoner's description, which appear to be localized in either space or time and sometimes both, where scattering between itinerant electrons and topological excitations such as skyrmions, vortices, various forms of instantons, emergent magnetic monopoles, and etc. may catch nonperturbative local physics beyond the Stoner's paradigm. In this review article we discuss nonperturbative effects of topological excitations on dynamics of correlated electrons.


번호 제목 날짜 조회 수
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 1058776
682 2022학년도 2학기 콜로퀴움 일정 2022.06.22 785
681 <July 8(Fri.)>Intertwined magnetism and charge density wave in a kagome metal 2022.06.03 907
680 <May 18(Wed.)>Magnetoresistance and Hall effects of Fe5Sn3 single crystals 2022.05.12 1134
679 <Apr. 27(Wed.)> I) A few first questions by me. II) ‘Topotactic resistance switching RAM’의 최초 발견 2022.04.20 1147
678 <May 11(Wed.)>Key Nuclear Experimental Studies to Find the Origin of Elements 2022.05.04 1221
677 <May 4(Wed.)>Recent progress in the study of topological phases of matter 2022.04.27 1226
676 <Apr. 20(Wed.)> 반도체 공정용 플라즈마 물리 2022.04.14 1265
675 <May. 10(Tue.)>Longitudinal magnon decay in the quasi-two-dimensional antiferromagnet in Ba2FeSi2O7 2022.05.09 1302
674 <May. 3(Tue.)>Anomalous Hall signatures of nonsymmorphic nodal lines in the doped chromium chalcospinel CuCr2Se4 2022.04.19 1406
673 <Mar. 30(Wed.)> Two-dimensional Semiconductors and their applications 2022.03.23 1612
672 <Mar. 16(Wed.)> 현세대/차세대 이차전지 기술 동향 및 전망 2022.03.02 1654
671 <Apr. 6(Wed.)> Holographic Flat Panel Displays 2022.03.30 1777
670 <Mar. 2(Wed.)>Introduction to high-energy nuclear physics 2022.02.24 2119
669 <Jan. 27(Thu.)>Emulating twisted double bilayer graphene with a multiorbital optical lattice 2022.01.18 2313
668 <Mar. 23(Wed.)> Next-generation artificial intelligence devices and physics 2022.03.16 2798
667 <Nov. 17(Wed.)>펜로즈의 삼각형과 블랙홀 - 부분과 전체 2021.11.11 4052
666 <Sep. 15(Wed.)> 강화학습 - 시행착오를 통해 배워나가는 인공지능 2021.09.08 5024
665 <Oct. 6(Wed.)> 블랙홀에서 쌍꺼풀수술까지 2021.09.29 5777
664 <Nov. 29(Mon.)>Exploring light-matter interactions at atomic scale using electron microscopy 2021.11.22 6632
663 <Nov. 10(Wed.)>Optical Spectroscopy of 2-Dimensional Materials 2021.11.03 7343