Post on 20-Dec-2015
Classical PhaseTransitions
Classical example:Phase diagram of H2O
Notice: 1st order and2nd order transitions
The ‘Standard Model’Fermi Liquid Theory and Metals
Non-classical ‘sharing’ of e- in ‘cond. band’
Band theory:
… more on metals
DOS – density of states
cV ~ T, ~ T2
Fermi Liquid Theory (Landau):
quasi-particles (excitations)in ‘sea’ of fermions
Metal-insulator transitions; Mott insulators
What is a Quantum Phase Transition?
Quantum fluctuationsb/c of Heisenberg uncertainty relation:no v=0 at T=0 can cause disruptions
Examples: magnetism in metals (FM / AFM)
superconductivity (‘pairing’ of electrons)
often combined with low dimensionality(constrained motion)
… more examples - HTSC
Laughlin etal Adv PhysThe bigger picture: HF vs SC phase diagrams
Lee, CQP AFM vs SC
… more examples: fract. QH Eff.
Hall Effect:Lorentz force causesdrift F= q(E+v x B)
Quantum Hall Effect(1994):Quantized ~ h/e2
Fractional QHEquantized in non-integersteps
Comprehensive Literature List
Monographs:In Physics and Electronics ed. JMT ThompsonDKK Lee AJ Schofield ‘Metals without Electrons: The Physics of Exotic Quantum Fluids’Some figures taken from Kittel and from Omar
Review Articles:Coleman Schofield Nature 433 2005, Quantum Criticality’Laughlin, Longzarich, Monthoux, Pines Adv Phys 50(361)Hertz 1976 PRB 14
Research Articles:Nature 425 2003 Doiron-Leyraud et al (Longzarich)Nature 424 2003 Custers (Steglich) The break up of heavy electrons at a QCPNature 414 2001 Hill Breakdown of FL theory in a cuprate SC Nature 441 2006 Sebastian Nature 441 2006 Erwin ‘When is a metal not a metal?’