Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Tiefe Temperaturen
TT 27: Symposium Twenty Years High-Tc Cuprates - Recent Progress
TT 27.5: Fachvortrag
Donnerstag, 30. März 2006, 12:00–12:30, HSZ 02
Spin-fluctuation mechanism of high-temperature superconductivity — •Andrey Chubukov — Physics, UW-Madison, 1150 University ave, Madison, WI 53706, USA
I will review the spin-fluctuation approach to high-temperature superconductivity. The key idea behind the approach is to depart from relatively high dopings, where fermions form Landau Fermi liquid, and consider how the 2D system behavior evolves as the system approaches an antiferromagnetic instability. I show that in the normal state, spin fluctuations are overdamped. The interaction with overdamped spin fluctuations gives rise to the fermionic self-energy which mimics marginal Fermi-liquid behavior over a wide range of frequencies. I next consider the pairing and show that there exists two regimes on the phase diagram: the low-T regime, in which the pairing involves Fermi-liquid quasiparticles, and the high -T regime, in which the pairing involves incoherent fermions. I argue that Fermi-liquid pairing leads to a $d-$wave superconductivity, while the pairing of incoherent fermions produces spin-singlet pairs, which still remain incoherent and do not carry a supercurrent. I discuss various feedbacks from the pairing on both electronic and magnetic properties (including the emergence of the resonance peak), and link spin-fluctuation approach to theories that depart from a Mott insulator at half-filling.