korean english


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



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 1929
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 813339
28 <10/13> 물리학과 저차원 스핀계 연구팀 초청 세미나 2006.10.11 74260
27 <9/7> Solitons in the Higgs phase 2006.09.05 76170
26 <8/17> Is Quantum Criticality a Key to Unconventional Superconductivity? 2006.08.09 76891
25 <5/22> 정상욱 교수 초청 세미나 Overview of Multiferroics 2006.05.19 72239
24 <5/3> High-Speed MOSFET Technology: State-of-the-Art Strain Engineering 2006.05.02 98204
23 <4/28> Generalised cosmological scaling solutions in braneworld and their duality properties 2006.04.24 80162
22 <2/27> Carbon nanotubes as Electron Sources 2006.02.21 77582
21 Square lattice S=1/2 Heisenberg spin systems: Vanadium oxides and phosphates 2006.01.12 73368
20 <12/12> lattice structure in holographic models 2012.12.12 68796
19 <12/21(금)> Theory of topological quantum phase transitions in 3D noncentrosymmetric systems 2012.12.05 79287
18 <12/21(금)> Generic quantum spin ice 2012.12.03 69412
17 <11/28> Extremal Black Holes and Holographic C-theorem 2012.11.28 71590
» <12/3> Magnetic couplings, optical spectra, and spin-orbit exciton in 5d Mott insulator Sr2IrO4 2012.11.26 181476
15 <11/21> Cosmological viable scalar-tensor theories of gravity 2012.11.16 81879
14 <11/5> Optical spectroscopic probe on the surface state in three dimensional topological insulators 2012.10.24 69321
13 <10/24> Dung-hai Lee 교수와의 간담회 2012.10.23 66351
12 <11/22> Spin polarization of photoelectrons from a topological insulator 2012.10.22 65968
11 <10/23> Measuring Transfer Reactions with Radioactive Beams 2012.10.15 70514
10 <10/12> Kondo Effect in a Quantum-Dot-Topological-Superconductor Junction: A Numerical Renormalization Group Analysis 2012.10.08 72339
9 <10/5> Gauge fields. Past, present, future. 2012.10.05 64672