Text Only Queen's U. Directory Contact: Queen's  |  Physics
 queensu.ca   physics.queensu.ca    


Home

............................................

  General Information

............................................
 
Contact Us

.....................................
 
Maps and Directions

.....................................
 
Colloquia and Talks

.....................................
 
Department News

.....................................
 
Employment

.....................................
 
Facilities

.....................................
 
IT Support

.....................................
 
About Queen's

.....................................
 
About Kingston

.....................................

Undergrad Studies

............................................

Graduate Studies

............................................

Research Groups

............................................

Faculty & Staff

............................................

Alumni & Friends

............................................

Visitors & Residents

............................................

Queen's Observatory

............................................

 
 Upcoming Talks        Past Talks        Calendar View

Condensed Matter Physics Seminar


LiV204: A frustration induced heavy fermion metal

Dr. John Hopkinson
Dept of Physics, U. of Toronto

Time
 
Wed. October 20, 2004     10:30 AM     Stirling 501

Abstract
 
How does the interplay of mixed valence and geometric frustration result in a heavy fermion state for LiV2O4?. I will briefly review the experimental evidence for the heavy fermion state realized in this compound in contrast to that seen in isostructural ZnV204 (an S=1 Mott insulator) and LiTi2O4 (a BCS superconductor). Unlike in conventional heavy fermions, 'conduction electrons' and 'localized electrons' here both originate from the d-electrons of the magnetic sites, leading to unusual properties of the resistivity at high temperatures as the 'conduction electrons' begin to localize. Within our proposed two-stage spin-quenching scenario, local valence flucutations are responsible for the formation of partially quenched, spin-1/2 moments below room temperature. Frustration of the intersite spin couplings then drives the system to realize the heavy Fermi liquid seen at low temperatures, providing a natural explanation for the sign change of the Hall coefficient along the way. A simplified square lattice version will be presented for illustration. A unique symmetry is predicted for the pyrochlore solution which has implications for the nature of the heavy quasiparticles observed.

List of upcoming talks and colloquia

Calendar for the current month



  Back to top
©2013 Department of Physics, Engineering Physics & Astronomy
Queen's University
Kingston, Ontario
K7L 3N6 Canada
Web Inquiries
webmaster@physics.queensu.ca
Departmental Inquiries
dept@physics.queensu.ca