logo

korean english

게시판

Home > 게시판 > 세미나

○ Date : 2015년 11월 13일(금) 오후 4:00
○ Place :  기초학문관 3층 창조존

○ Speaker : 이  현  정  박사님 (KAIST)
○ Topic : Kondo screening in mixed valence and heavy fermion compounds and the signatures of Nozieres’ exhaustion


○ Abstract: 

Whereas most rare-earth compounds with the stable valence show concomitant local magnetic moments which order magnetically at low temperature, the mixed-valence compounds have avoided local magnetism of the rare earths through the hybridization process between the degenerate valence states. To understand the relation of this hybridization with the Kondo effect, it is necessary to have a low energy Hamiltonian for the lattice problem with which one can answer questions like what determines the coherence scale in the Kondo problem and answer questions such as the exhaustion paradox raised by P. Nozieres [Ann. Phys. (Paris) 10, 19, (1985)].



To investigate the exhaustion problem in Kondo lattices, we examine the dynamical properties of the periodic Anderson model such as the local spectral density and the spin excitation spectrum within the dynamical mean-field theory using the numerical renormalization-group technique. Pursuing the high impurity-concentration and the strong coupling limit simultaneously, we find a transition between coherent and incoherent Kondo regime, characterized by closing of the hybridization gap and appearance of Fano resonance. The appearance of the Fano resonance is attributed to coherent valence fluctuation which leads to a polaron like depression of the density of states near the van Hove singularity in the conduction band. We discuss the competing mechanism between the two screening channels, i.e. spin and valence fluctuations, and the relevance to the quantum criticality exhibited in Yb based heavy fermion superconductors.



번호 제목 날짜 조회 수
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 1009092
462 <7월27일>Correlated topological phases in 3D complex oxides via Green's functions 2012.07.27 84747
461 <4/5(Wed.) 11:00am>Adhesion forces between nanoparticles in gas-phase processes and application 2017.04.03 84644
460 <11/11> Revealing magnetism of nanoislands with quantitative insights into spin-polarized scanning tunneling spectroscopy 2013.11.05 84626
459 <5/29> Study on the electronic interactions in solids under high magnetic fields 2013.05.23 84624
458 <June 10(Thu.)>Oxide electronics utilizing spin-orbit coupling 2021.05.31 84554
457 <10/8(수> Astrophysical probes of Dark Matter, the case of the Milky Way 2014.10.01 84519
456 <10/12> Kondo Effect in a Quantum-Dot-Topological-Superconductor Junction: A Numerical Renormalization Group Analysis 2012.10.08 84115
455 <Sep. 30(Wed.) 4:30 PM>Local electronic structures of stacking grain boundary in bilayer graphene 2015.09.23 83996
454 <7/21> Next generation cryogenic free 1.5T MgB2-magnet based MRI 2010.07.20 83935
453 <12/14> Breakup-Fusion and Knockout-Fusion Approach to Pre-Equilibrium Processes 2009.12.11 83771
452 콜로퀴움 강연 일정표 2006.02.21 83617
451 <10/17> The Interface Induced Magnetism 2012.10.11 83600
450 <10/13> 물리학과 저차원 스핀계 연구팀 초청 세미나 2006.10.11 83597
449 <12/21(Fri) 3:00pm ~ > Quasilocal Smarr Relations / Expanding Universe and Dynamical Compactification Using Yang-Mills Instantons 2018.12.17 83545
448 <5/16(Thu.) 14:00 ~ >The Chiral anomaly without Landau levels 2019.05.08 83544
447 <11/7> Two- and three- body problems in classic and quantum mechanics 2012.10.29 83439
446 <3/23> 동서양의 세계관과 풍경화 2011.03.17 83425
445 <9/26(Thu.) 4:30 pm ~ > Neutrino Physics and Dark Matter search in IBS 2019.09.24 83364
444 <11/23> How statistical physics contributes to Internet world: perspectives, methods and applications 2011.11.15 83231
443 <Oct.20(Tue) 16:00> Electromagnetic Response and Thermomagnetic Instabilities in Three-Dimensional Nanostructured Superconductors file 2015.10.15 83025