korean english


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 1088851
636 <May.30(Wed.) 4:30 PM> 구리산화물 고온 초전도체의 특성과 응용 2018.05.23 45915
635 <Nov.21(Wed.) 4:30 PM> 핵물리학과 RAON 2018.11.15 45995
634 <Mar.31(Wed.)> Nonlinear nanophotonics using on-chip microring resonator 2021.03.25 46262
633 <Mar.7(Wed.) 4:30 PM>Acoustic metamaterial: principles and applications of phononic crystals 2018.03.02 46591
632 <Nov. 1(Wed.) 4:30 PM> 광자와 이온트랩을 이용한 양자 정보처리 2017.10.25 46694
631 <May.23(Wed.) 4:30 PM> 한국 희귀동위원소과학 프로젝트(Rare Isotope Science Project in Korea) 2018.05.16 46707
630 <June 01(Tue.)>Frustration-induced Athermal Behaviors: Hilbert Space Fragmentation and Quantum Many-Body Scars 2021.05.24 46735
629 <Nov.29(Wed.) 4:30 PM> The Intensity Frontier Experiment & SHiP 2017.11.22 46776
628 <July 14(Wed.)> B1g phonon anomaly driven by Fermi surface instability at intermediate temperature in YBa2Cu3O7−δ 2021.07.13 47020
627 <Mar.21(Wed.) 4:30 PM>깊은 땅속 중성미자 실험, DUNE 2018.03.14 47330
626 <Sep. 6(Wed.) 4:30 PM> Particles in the Universe 2017.09.01 47377
625 <April.3(Wed.)> 전자구조계산을 이용한 새로운 양자물질 연구 2019.03.27 47681
624 <Sep. 20(Wed.) 4:30 PM> 양자이론에 대한 `서울해석` 시도하기 2017.09.13 47775
623 <Sep. 13(Wed.) 4:30 PM> 우주론 100년, 어디로 가고 있는가? 2017.09.06 48594
622 <April.10(Wed.)> 자성 반데르발스 물질 발견과 전망(Discovery and Perspective of magnetic van der Waals materials) 2019.04.04 49053
621 <4/5(Wed.) 18:00pm> 저에너지 가속기의 활용 2017.04.05 50035
620 <April.11(Wed.) 4:30 PM>History of Superconductivity and its Future 2018.04.04 50151
619 <11/6(Tue.) 3:00pm>The Surprising Solar Gamma-ray Emission from Cosmic-Ray Interactions 2018.11.03 50202
618 <Oct. 13(Wed.)> Electric Quantum Oscillation: A New Form of Quantum Oscillation 2021.10.06 50276
617 <Nov. 5(Fri.)>Strongly Coupled Moire Photonics 2021.11.01 50413