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 1078554
625 <11/11>Leptogenesis in triplet seesaw models 2006.11.08 142357
624 2021학년도 1학기 콜로퀴움 일정 2021.01.13 141830
623 <12/26> Emergent Physics in 3D Correlated Topological Semimetals file 2013.12.20 141691
622 <April. 6(Wed.) 4:30 PM> Quantitative Determination of High Tc Superconductivity Mechanism 2016.03.31 141630
621 2018학년도 2학기 콜로퀴움 일정 2018.07.03 141504
620 <9/26> Organic Polymers as Nuclear Radiation Sensors 2012.09.20 140126
619 <Oct. 20(Tue.) 2:00 PM> High-throughput Synthesis of Oxide Thin Films 2015.10.05 139375
618 <5/30> DNA 나노기술(DNA Nanotechnology) 2008.05.26 139355
617 <11/22>A Glimpse of X-ray Sky 2006.11.16 139036
616 <5/2>방사선을 이용한 무통/무혈 수술 2008.04.28 137946
615 <Oct.16(Wed.)> 솟구치는 초고에너지 입자의 미스테리 2019.10.10 136290
614 <11/6> Scaling laws between facility and population densities 2009.11.04 135847
613 2021학년도 2학기 콜로퀴움 일정 2021.07.01 134871
612 2016학년도 1학기 콜로퀴움 일정 2016.02.03 133724
611 <12/21(금)> Theory of topological quantum phase transitions in 3D noncentrosymmetric systems 2012.12.05 133175
610 <5/3> High-Speed MOSFET Technology: State-of-the-Art Strain Engineering 2006.05.02 131748
609 <3/27>Social Experience, Brain, and Behavior 2009.03.23 130890
608 <4/4> Novel multi-bit magnetic tagging technique for high-throughput chemical analysis 2008.03.31 129869
607 <7/25(목) 오전11시> 물리학과 특별세미나 개최 안내 2013.07.19 129541
» <Nov.13(Fri) 16:00> Kondo screening in mixed valence and heavy fermion compounds and the signatures of Nozieres’ exhaustion 2015.11.04 129371