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 1091807
699 <Dec. 15(Thur.)>Pseudogap and topological phase transition in black phosphorus 2022.12.08 9
698 <Dec. 9(Fri.)>Confirming Topological Materials by ARPES 2022.12.02 26
697 <Dec. 20(Tue.)>Studying TeV Gamma-Ray Microquasars with the HAWC Observatory 2022.12.01 33
696 <Nov. 21(Mon.)> Strong magneto-elastic coupling observed in ultrafast lattice dynamics of SrRuO3 based superlattices 2022.11.15 47
695 <Nov. 23(Wed.)> 단백질 구조예측과 알파폴드의 물리학 2022.11.17 61
694 <Nov. 16(Wed.)> 원자핵의 존재 한계를 찾아서 2022.11.11 65
693 <Nov. 11(Fri.)> On the origin of CDW in two-dimensional materials 2022.11.04 97
692 <Nov. 11(Fri.)> Nonvanishing anomalous Hall effect in Mn3Al- compensated ferrimagnetic Heusler compound 2022.11.08 103
691 <Nov. 2(Wed.)> The latest from quantum Hall effect in graphene family 2022.10.27 159
690 <Oct. 26(Wed.)>Atomic-scale observation of structural phase transition of strontium ferrite 2022.10.22 176
689 <Oct. 5(Wed.)>“사라진 중성미자를 찾아서” 2022.09.29 247
688 <Sep. 21(Wed.)>Dynamics and thermodynamics of bimolecular reactions at aqueous-nonaqueous interfaces 2022.09.15 324
687 <Nov. 9(Wed.)> 천체와 우주의 진화에서 보는 원소의 기원 2022.11.02 457
686 <Sep. 14(Wed.)>The Next Generation of Photonic Sources – Light-Emitting Devices 2022.09.08 555
685 <Sep. 7(Wed.)>Flavor of particles, as a key for New physics 2022.09.01 573
684 <Oct. 12(Wed.)>Neurodegenerative Diseases from the Chemical Force Point of View 2022.10.05 1034
683 2022학년도 2학기 콜로퀴움 일정 2022.06.22 1717
682 <May 4(Wed.)>Recent progress in the study of topological phases of matter 2022.04.27 1785
681 <May 18(Wed.)>Magnetoresistance and Hall effects of Fe5Sn3 single crystals 2022.05.12 1794
680 <Apr. 20(Wed.)> 반도체 공정용 플라즈마 물리 2022.04.14 1827