Dr. Walter Metzner
Max Planck Institute for Solid State Research, Stuttgart, Germany
Gauge Theory of the Pseudogap Phase in Cuprate Superconductors
Location: 1080 Physics Research Building, Smith Seminar Room
Faculty Host: Nandini Trivedi
Abstract: The pseudogap phase in cuprate superconductors is one of the most
intriguing challenges in the theory of high temperature superconductivity.
In this talk we elaborate on the hypothesis that pseudogap phenomena are
mostly due to strong magnetic fluctuations. Using the two-dimensional
Hubbard model to describe the electrons in the copper-oxygen planes of the
cuprates, a gauge theory of fluctuating magnetic order is formulated and
analyzed [1]. The theory is based on a fractionalization of electrons in
fermionic chargons with a pseudospin degree of freedom and bosonic
spinons, which leads to a SU(2) gauge redundancy. The chargons undergo
Neel or spiral magnetic order below a density dependent transition
temperature T*. Fluctuations of the spin orientation are described by a
non-linear sigma model obtained from a gradient expansion of the spinon
action. The spin stiffnesses are computed from a renormalization group
improved random phase approximation. The spinon fluctuations prevent
magnetic long-range order of the electrons at any finite temperature. The
phase with magnetic chargon order exhibits many features characterizing
the pseudogap regime in high-Tc cuprates: a strong reduction of charge
carrier density, a spin gap, and Fermi arcs. A substantial fraction of the
pseudogap regime exhibits electronic nematicity.
[1] P. M. Bonetti and W. Metzner, Phys. Rev. B 106, 205152 (2022).
Bio: Study of physics TU Munich, doctorate Technical Univ. Aachen (1989), postdoc in Rome and Princeton, German Habilitation in physics, Techn. Univ. Aachen (1995), Associate Professor Univ. Munich (1996), Full Professor Techn. Univ. Aachen (1998), Director and Scientific Member at the Max Planck Institute for Solid State Research (since 2001), Honorary Professor Univ. Stuttgart (2002).
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Meeting ID: 962 2464 1621
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