Condensed Matter Physics Seminar

2 p.m., Thursday, February 22, 2001
Room 1201, Physics Building

2D fermions near an antiferromagnetic instability: non-Fermi-liquid behavior and pairing

Andrei Chubukov

(Department of Physics, University of Wisconsin, Madison)

Abstract: In this talk, I will consider the properties of 2D fermions near the boundary of the antiferromagnetic phase. This problem is relevant to both cuprates and heavy fermion materials. I focus on the situation when spin decay is allowed, i.e., at a mean-field level, the magnetic transition has a dynamical exponent z=2. For this problem, the RG consideration yields a marginal behavior at criticality. I show, however, that the actual situation is more complex due to the presence of anomalies, hidden from RG treatment. I argue that

The fermionic behavior is not marginal, and is more a non-Fermi liquid one, than one would expect from the RG study.
The dynamic exponent z is different from 2.
As a peculiar consequence of a non-Fermi liquid behavior, the system at criticality is unstable towards a non-BCS pairing.

I discuss the meaning of these results for cuprates.

Host: Victor Yakovenko

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