logo

korean english

게시판

Home > 게시판 > 세미나

아래와 같이 세미나를 개최하오니 많이 참석해 주시기 바랍니다.

 

                    아       래

 

제목: Magnetic couplings, optical spectra, and spin-orbit exciton in 5d Mott insulator Sr2IrO4

 

연사: 김  범  현 박사님 (포항공대) 

 

일시: 2012년 12월 3일 오후 2시 

 

장소: 학술정보관 프리젠테이션룸

 

초록:

Recently, a new class of 5d Mott insulator Sr2IrO4 has been discovered. In this system, the strong spin-orbit (SO) coupling as well as the Coulomb interaction is crucial for stabilizing the insulating state. Its 5d5 shell splits into half filled Jeff=1/2 and fully-occupied Jeff=3/2 state due to strong SO coupling. The narrow half filled Jeff=1/2 band tends to undergo a Mott transition under relatively small Coulomb repulsion. Thus, it is referred to as Jeff=1/2 Mott insulator.[1]

Because of strong SO coupling, Sr2IrO4 shows intriguing physical properties which do not appear in conventional 3d Mott insulators. The resonant inelastic scattering (RIXS) experiments have observed higher energy broad peak at ~0.5-0.8 eV, termed SO exciton[2]. The optical conductivity s(w) of Sr2IrO4 shows two peaks at ~0.5 eV and ~1.0 eV[1]. Simple interpretation based on picture of single-electron density of state insists that the first peak was assigned to the transition from occupied to unoccupied Jeff=1/2 band, while the second peak to that from occupied Jeff=3/2 to unoccupied Jeff=1/2 band. However, there has been no theoretical calculation of s(w) taking into account the many-electron multiplet structure of excited states.

We have calculated the magnetic coupling, optical conductivity, and RIXS spectra in by exact diagonalization of a microscopic model on small clusters, fully incorporating the multiplet structure of Ir ions. Magnetic couplings are consistent with the available data. Calculated RIXS spectra reproduce the SO exciton mode. We also found that two peak structure of s(w) arises from the unusual Fano-type overlap between the electron-hole continuum of the Jeff=1/2 band and the intrasite SO exciton[3].

                                                                                   

[1] B. J. Kim et. al., Phys. Rev. Lett. 101, 076402 (2008)

[2] J. Kim et. al., Phys. Rev. Lett. 108, 177003 (2012)

[3] B. H. Kim, G. Khaliullin, and B. I. Min, Phys Rev Lett, 109, 167205 (2012)

번호 제목 날짜 조회 수
공지 2022학년도 1학기 콜로퀴움 일정 2022.01.10 3439
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 816373
667 2019학년도 2학기 콜로퀴움 일정 2019.07.17 405854
666 2020학년도 1학기 콜로퀴움 일정 2020.01.31 243469
665 2017학년도 1학기 콜로퀴움 일정 2017.01.05 195060
» <12/3> Magnetic couplings, optical spectra, and spin-orbit exciton in 5d Mott insulator Sr2IrO4 2012.11.26 186455
663 <5/16(토)> 세미나 개최 안내 2015.05.18 143819
662 2016학년도 1학기 콜로퀴움 일정 2016.02.03 128027
661 2020학년도 2학기 콜로퀴움 일정 2020.07.16 123307
660 <4/2> Radio Detection of Ultra High Energy Cosmic Rays and Neutrinos in Antarctica 2014.03.26 115730
659 2019학년도 1학기 콜로퀴움 일정 2019.01.08 114968
658 2018학년도 2학기 콜로퀴움 일정 2018.07.03 112063
657 <11/7> On-Film Formation of Bi Nanowires with Extraordinary Electron Mobility 2008.11.03 108622
656 2021학년도 1학기 콜로퀴움 일정 2021.01.13 107586
655 <11/11>Leptogenesis in triplet seesaw models 2006.11.08 105846
654 <5/26>BK21 물리연구단 석학초빙 특별 세미나 2010.05.17 105031
653 2018학년도 1학기 콜로퀴움 일정 2018.01.03 104353
652 <12/3> Characteristic of risk asset in financial market. 2010.11.29 104240
651 2017학년도 2학기 콜로퀴움 일정 2017.07.04 101483
650 2014학년도 2학기 콜로퀴움 일정 2014.09.11 101075
649 <3/13> Probing hidden magnetism and quantum criticality in unconventional superconductors 2009.03.06 100293