logo

korean english

게시판

Home > 게시판 > 세미나

아래와 같이 세미나를 개최하오니 많이 참석해 주시기 바랍니다.

 

아 래

   

제목: Emergent Physics in 3D Correlated Topological Semimetals 

 

연사: 양   범  정 박사님 (RIKEN)

 

일시: 2013. 12. 26(목) 오후 4:00

 

장소: 제1과학관 물리학과 2층 라운지세미나실

 

 

초록: Recently, there has been a surge of research interests in the physics of the 3D semimetal, which is so-called the Weyl semimetal. The Weyl semimetal is composed of several Fermi points around which the electron shows the linear dispersion relation in all three momentum directions. Because of the nontrivial topological property of the Fermi point, the Weyl semi-metal shows several topologically nontrivial properties such as the Fermi Arc and quantum Hall effects. In this talk, I’d like to introduce the novel physical properties of the 3D interacting Weyl semimetal and its associated quantum critical phenomena. My talk is composed of two parts. The first part is about the emergent topological phenomena in pyrochlore iridates, one promising candidate material supporting Weyl semimetals. Due to the recent development of thin film and artificial superstructure growth technique, it is possible to control the dimensionality of the system, smoothly between the two-dimensions (2D) and three-dimensions (3D). In this work we unveil the dimensional crossover of emergent topological phenomena in correlated topological materials. In particular, by focusing on the thin film of pyrochlore iridate antiferromagnets grown along the [111] direction, we demonstrate that it can show giant anomalous Hall conductance, which is proportional to the thickness of the film, even though there is no Hall effect in 3D bulk material. In addition, we uncover the emergence of a new topological phase, whose nontrivial topological properties are hidden in the bulk insulator but manifest only in thin films. This shows that the thin film of topological materials is a new platform to search for unexplored novel topological phenomena.


The second part of my talk is about the quantum criticality of the topological phase transition associated with the Weyl semimetal. Topological phase transitions in condensed matters accompany emerging singularities of the electronic wave function, often manifested by gap-closing points in the momentum space. In conventional topological insulators in three dimensions (3D), the low energy theory near the gap-closing point can be described by relativistic Dirac fermions coupled to the long range Coulomb interaction, hence the quantum critical point of topological phase transitions provides a promising platform to test the novel predictions of quantum electrodynamics. Here we show that a new class of quantum critical phenomena emanates in topological materials breaking either the inversion symmetry or the time-reversal
symmetry. At the quantum critical point, the theory is described by the emerging low energy fermions, dubbed the anisotropic Weyl fermions, which show both the relativistic and Newtonian dynamics simultaneously. The interplay between the anisotropic dispersion and the Coulomb interaction brings about a new screening phenomenon distinct from the conventional Thomas-Fermi screening in metals and logarithmic screening in Dirac fermions.

 

번호 제목 날짜 조회 수
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 1058712
622 <5/2>방사선을 이용한 무통/무혈 수술 2008.04.28 136047
621 <11/11>Leptogenesis in triplet seesaw models 2006.11.08 134080
620 <April 7(Wed.)> Mid-scale facilities for condensed matter research: high magnetic field and neutron scattering 2021.03.31 133734
619 2016학년도 1학기 콜로퀴움 일정 2016.02.03 133091
618 <9/26> Organic Polymers as Nuclear Radiation Sensors 2012.09.20 131053
» <12/26> Emergent Physics in 3D Correlated Topological Semimetals file 2013.12.20 130139
616 <4/6> Knowledge is power: Maxwell's demon in the quantum wonderland 2011.03.31 129972
615 <11/6> Scaling laws between facility and population densities 2009.11.04 128805
614 <April. 6(Wed.) 4:30 PM> Quantitative Determination of High Tc Superconductivity Mechanism 2016.03.31 128110
613 <5/30> DNA 나노기술(DNA Nanotechnology) 2008.05.26 127607
612 2021학년도 2학기 콜로퀴움 일정 2021.07.01 126850
611 <Oct. 20(Tue.) 2:00 PM> High-throughput Synthesis of Oxide Thin Films 2015.10.05 126751
610 <5/3> High-Speed MOSFET Technology: State-of-the-Art Strain Engineering 2006.05.02 126747
609 2019학년도 1학기 콜로퀴움 일정 2019.01.08 125447
608 <12/3> Characteristic of risk asset in financial market. 2010.11.29 124744
607 <Oct.16(Wed.)> 솟구치는 초고에너지 입자의 미스테리 2019.10.10 122912
606 <3/27>Social Experience, Brain, and Behavior 2009.03.23 122653
605 <12/21(금)> Theory of topological quantum phase transitions in 3D noncentrosymmetric systems 2012.12.05 121946
604 <Nov.13(Fri) 16:00> Kondo screening in mixed valence and heavy fermion compounds and the signatures of Nozieres’ exhaustion 2015.11.04 121448
603 <5/29> Nanomaterials Work at NASA-Johnson Space Center 2009.05.25 121366