Quantum solids, liquids, and gases program:Nernst effect as a probe of broken symmetries in the normal state of cuprate materials

by Andreas (California Institute of Technology), Hackl (California Institute of Technology)

Friday 30 Jul 2010, 11:00 → 12:00 Europe/Stockholm

Experiments on underdoped cuprate superconductors suggest an intricate relation between the normal-state Nernst effect and stripe order: The Nernst signal appears enhanced near 1/8 hole doping and its onset temperature scales with the stripe-ordering temperature over some range of doping. Here, we analyze the thermoelectric response in layered metals with spontaneously broken rotation or translation symmetry. For broken rotation symmetry we identify the anisotropy of the quasiparticle Nernst signal as an extremely sensitive probe of Fermi surface distortions characteristic of the ordered state. Applied to recent experiments, our results reinforce the proposal that the underdoped cuprate superconductor YBCO displays such "electron-nematic" order in the pseudogap regime. Furthermore, we find that Fermi pockets caused by translational symmetry breaking lead to a strongly enhanced Nernst signal with a sign depending on the modulation period of the ordered state and other details of the Fermi surface. We compare our findings with recent data from Nd-LSCO and YBCO.