Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 68: Correlated Electrons: (General) Theory 1
TT 68.9: Vortrag
Mittwoch, 18. März 2015, 17:30–17:45, H 3010
Fluctuation diagnostics of the electron self-energy: Origin of the pseudogap physics — Olle Gunnarsson1, Thomas Schäfer2, James Le Blanc3,4, Emanuel Gull4, Jaime Merino5, Giorgio Sangiovanni6, Georg Rohringer2, and •Alessandro Toschi2 — 1Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany — 2IFP, Vienna University of Technology, Austria — 3Max-Planck-Institute for the Physics of Complex Systems, Dresden, Germany — 4Department of Physics, University of Michigan, Ann Arbor, USA — 5Departamento de Física Teórica de la Materia Condensada, IFIMAC Universidad Autónoma de Madrid, Spain — 6Institute of Physics and Astrophysics, University of Würzburg, Germany
We demonstrate how to identify which physical processes dominate the low-energy spectral functions of correlated electron systems. We obtain an unambiguous classification by analysing the equation of motion for the electron self-energy in its charge, spin and particle-particle representations. Our procedure is then employed to clarify the controversial physics responsible for the appearance of the pseudogap in correlated systems. We illustrate our method by examining the attractive and repulsive Hubbard model in two-dimensions. In the latter, spin fluctuations are identified as the origin of the pseudogap, and we also explain why d-wave pairing fluctuations play a marginal role in suppressing the low-energy spectral weight, independent of their actual strength.