Destruction of Cuprate Superconductivity with Current: a Variational Study

Speaker: Lilach Goren, Weizmann Institute

When: March 25, 2010 (Thu), 10:00AM to 11:00AM (add to my calendar)

This event is part of the Condensed Matter Theory Seminar Series.

Abstract:
We investigate the properties of cuprate superconductors subject to
applied current, using modified Gutzwiller projected d-wave BCS
states. The parent wave-functions include quasiparticle and quasihole
pockets, of variationally determined size, generated by the current.
The pockets, growing with increasing current, contribute to the
reduction of the superfluid stiffness and its eventual destruction. We
identify two different mechanisms which determine the critical
current: at high hole doping (x>0.15) it occurs when the pockets
completely destroy the gap, in a BCS-like mechanism; in the underdoped
regime the mechanism is bosonic, whereby the critical current is set
by a maximal phase twist which destroys the superfluid stiffness with
pairing still intact. This result is indicative of a pseudogapped
‘normal’ state which retains pairing correlations. The critical
current as a function of doping displays a dome shape, similar to Tc.
We predict unique signatures of the current induced Fermi pockets that
can be seen in ARPES measurements.