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 1088717
220 <8/5(Fri.) 10:30> Phase Slips in Superfluid Spin Transport in Magnetic Wires 2016.08.02 57976
219 <7/18(Mon.) 14:00> GEANT4 Particle Physics Simulation Software: A Brief Overview From a User’s Perspective 2016.07.15 69738
218 <7/15(Fri.) 11:00> Observation of a field induced quantum spin liquid in α-RuCl3 2016.07.14 69827
217 <7/15(Fri.) 14:00> Electronic quasiparticles in the quantum dimer model 2016.07.12 71566
216 <7/12(Tue.) 11:00> Spin-direction-dependent magnetoelastic coupling on MnO, CoO, and NiO file 2016.07.01 79110
215 <6/24(Fri.) 1:30pm>Emergent geometry from field theory: Wilson's renormalization group revisited 2016.06.20 70105
214 <May.27(Fri.) 10:00> Towards Magnetic 2D Materials 2016.04.27 89815
213 <April 25(Mon) 16:30> Neutron Recoil Polarization in Low‐energy Photodisintegration of the Deuteron 2016.04.25 54119
212 <4/6(Wed.) 1pm> Results from DM-Ice17 2016.04.05 83416
211 <March.24(Thu) 14:00> A new boson and muon g-2 2016.03.17 67857
210 <March.18(Fri) 11:00> High Pressure Synthesis and Characterization of Non-Oxide Superconductors 2016.03.14 71593
209 <March 8(Tue) 18:00> Unsolved puzzles of Gamma-Ray Bursts 2016.03.03 74482
208 <Dec.30(Wed) 16:30> Some basics about the thermoelectricity; the semi-classical Boltzmann transport approach 2015.12.24 70128
» <Nov.13(Fri) 16:00> Kondo screening in mixed valence and heavy fermion compounds and the signatures of Nozieres’ exhaustion 2015.11.04 134572
206 <Oct.20(Tue) 10:00-12:00> Novel quantum transport in Weyl semimetals and double-Weyl semimetals 2015.10.23 96372
205 <Oct.20(Tue) 16:00> Electromagnetic Response and Thermomagnetic Instabilities in Three-Dimensional Nanostructured Superconductors file 2015.10.15 103918
204 <Oct.15(Thu) 16:30> Single-Molecule Approach to Homology Search & Strand Exchange in Homologous Recombination 2015.10.12 126069
203 <Oct. 20(Tue.) 2:00 PM> High-throughput Synthesis of Oxide Thin Films 2015.10.05 149604
202 학술세미나 개최 안내: Local Modes in Vibrational (and Rotational) Spectroscopy file 2015.10.01 56600
201 <Sep. 18(Fri.) 4:00 PM> Special seminar 2015.09.16 59240