Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: Low-Dimensional Systems: 2D - Theory (TT jointly with O)

O 44.11: Vortrag

Mittwoch, 2. April 2014, 12:15–12:30, BEY 81

Superconductivity in the two-dimensional t-t′-Hubbard model — •Andreas Eberlein and Walter Metzner — Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany

Using a recently developed renormalization group method for fermionic superfluids, we determine conditions for d-wave superconductivity in the ground state of the two-dimensional Hubbard model at moderate interaction strength, and we compute the pairing gap in the superconducting regime. A pairing instability signaled by a divergent flow in the Cooper channel leads to a superconducting state in all studied cases. The next-to-nearest neighbor hopping t′ plays a crucial role in the competition between antiferromagnetism and superconductivity. A sizable t′ is necessary to obtain a sizable pairing gap.