Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: Correlated Electrons: Quantum-Critical Phenomena

TT 19.14: Vortrag

Dienstag, 26. Februar 2008, 17:45–18:00, H 3010

Critical Properties of an Effective Field Theory for 2D Doped Antiferromagnets — •Juergen Falb, Marcello Silva Neto, and Alejandro Muramatsu — Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, 70550, Stuttgart, Deutschland

Starting from the t−t^′−t^′′−J model for high-Tc cuprate superconductors we derive an anisotropic and gauge massive CP¹ effective field theory that describes the low energy magnetic properties at low doping, establishing a link between doped antiferromagnets on a bipartite lattice and frustrated quantum antiferromagnets [1]. We first discuss the generation of mass for the gauge field introduced by doping, and comment on the possible incommensurate phases associated to it. The massive gauge field opens the possibility of deconfined spinons in the symmetric phase. We find a region of stability for the microscopic parameters J,t^′ and t^′′ where the theory is valid. Through a renormalization group study of the theory in weak coupling we obtain its phase diagram. The connection between our results and previous works on the literature are also discussed.

[1] [t]8.7cmJ. Falb and A. Muramatsu, arXiv:0705.1918, accepted for publication in Nucl. Phys. B.