## Phenomenological Theory of the Pseudogap regime in the copper oxides

Speaker: Alexei Tsvelik, Brookhaven
Date & Time: January 30, 2007 - 1:30pm
Location: Serin 385E

Phenomenological Theory of the Pseudogap regime in the copper oxides
Physics and Astronomy

Alexei Tsvelik, Brookhaven
Serin 385E 1:30pm

We model the underlying Fermi surface of the cuprates by one-dimensional nested parts near $(0,\pi)$ and $(\pi,0)$ and unnested parts near the zone diagonals. Fermions in the nested regions form 1D spin liquids, and develop spectral gaps below some $\sim T^*$, but superconducting order is prevented by 1D phase fluctuations. We show that the Josephson coupling between order parameters at $(0,\pi)$ and $(\pi,0)$ locks their relative phase at a crossover scale $T^{**}< T^*$. Below $T^{**}$, the system response becomes two-dimensional, and the system displays Nernst effect. The remaining total phase gets locked at $T_c < T^{**}$, at which the system develops a (quasi-) long-range superconducting order.

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