Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 5: Correlated Electrons - (General) Theory

TT 5.13: Vortrag

Montag, 26. März 2007, 17:45–18:00, H18

Magnetic phases of the t-J model at low doping — •Juergen Falb, Marcello Barbosa da Silva Neto, and Alejandro Muramatsu — Institut für Theoretische Physik III, Universitaet Stuttgart, D-70550 Stuttgart, Germany

Based on the method of Dirac quantization for constrained systems, we set up a path integral for the t-J model. Spin degrees of freedom result in a unimodular vector field while dopant holes are spin 1/2 fermions. The constraint against double occupancy can be solved exactly by choosing spin quantization axes of the dopant holes that follow the local direction of the spins. Assuming a staggered spin field leads to staggered spinless fermions. A gradient expansion of the t-t’-t”-J model in the low doping limit leads to a CP¹ model with a coupling to the gauge fields different from 1. The possible magnetic phases in parameter space will be discussed.