Regensburg 2007 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 2: Quantum-Critical Phenomena
TT 2.8: Talk
Monday, March 26, 2007, 11:30–11:45, H19
Spontaneous Fermi surface symmetry breaking in Sr3Ru2O7 — •Hiroyuki Yamase and Andrey Katanin — Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
The most salient features observed around a metamagnetic transition in Sr3Ru2O7 are well captured in a simple model for spontaneous Fermi surface symmetry breaking under the Zeeman magnetic field, without invoking a putative quantum critical point. The Fermi surface symmetry breaking happens in both a majority and a minority band but with different magnitude of the order parameter, when either band is tuned close to van Hove filling by the magnetic field. The transition is second order for high temperature (T) and changes into first order for low T. The first order transition is accompanied by a metamagnetic transition. The uniform magnetic susceptibility and the specific heat divided by temperature show strong T dependence, especially logT divergence at van Hove filling. The Fermi surface instability then cuts off these non-Fermi liquid behaviors and gives rise to a specific heat jump and a cusp in the susceptibility at Tc.