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 1058919
602 <10/28>Grazing Incidence X-ray Diffraction and Surface X-ray Scattering Study of Hematite (α-Fe2O3) Nano-cube 2011.10.26 121045
601 <4/21> Experimental and Observational Astrophysics in the Infrared Wavebands 2009.04.17 120672
600 <5/1>In vivo optical imaging of hemodynamic changes 2009.05.06 120665
599 <4/4> Novel multi-bit magnetic tagging technique for high-throughput chemical analysis 2008.03.31 120275
598 <11/22>A Glimpse of X-ray Sky 2006.11.16 120223
597 <April.17(Wed.)> Emerging Artificial Synapse for Learning- and Energy-Efficient Neuromorphic System 2019.04.11 120101
596 <10/17> Graphitic Carbon Nanostructures 2008.10.27 119510
595 <3/19> Bioconjugates of nanomaterials for biochip & biosensor applications 2010.03.16 118799
594 <11/5> Modified nucleic acid systems for biomedical applications 2010.11.01 118018
593 <4/30> Updates on warped brane inflation 2009.04.21 117897
592 <3/12(화)>물리학과 특별초청강연 개최 안내 2013.03.04 116784
591 <3/31> ZnO nanorod heterostructures and nanodevices 2006.03.27 116454
590 <5/16(Thu.) 14:00 ~ >The Chiral anomaly without Landau levels 2019.05.08 116331
589 <5/15>Black Hole Entropy Function in (Anti-)de Sitter Space-Time 2008.05.09 115228
588 <4/14> X-ray absorption fine structure analyses on amorphous oxide films 2009.04.06 114966
587 <1/28> Steps towards a non-relativistic AdS/CFT 2010.01.25 114599
586 <12/30> Dirac vs. Weyl in topological insulators: Adler-Bell-Jackiw anomaly in transport phenomena 2013.12.16 113844
585 <8/5>Brane superpotential via local Calabi-Yau spaces 2009.08.03 113753
584 <7/20(Thu.)14:00>Engineering and probing topological properties of Dirac semimetal films by asymmetric charge transfer 2017.07.18 113016
583 <12/21(금)> Theory of topological quantum phase transitions in 3D noncentrosymmetric systems 2012.12.05 112930