Pseudogap and precursor superconductivity in underdoped cuprate high temperature superconductors: A far-infrared ellipsometry study

Dubroka, Adam; Yu, Li; Munzar, Dominik; Kim, KyungWan; Rössle, Matthias; Malik, Vivek Kumar; Lin, C.T.; Keimer, B.; Wolf, Th.; Bernhard, Christian

doi:10.1140/epjst/e2010-01298-7

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Journal article

Pseudogap and precursor superconductivity in underdoped cuprate high temperature superconductors: A far-infrared ellipsometry study

Dubroka, Adam Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
Yu, Li Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
Munzar, Dominik Institute of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic
Kim, KyungWan Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
Rössle, Matthias Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
Malik, Vivek Kumar Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
Lin, C.T. Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
Keimer, B. Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
Wolf, Th. Karlsruhe Institute of Technology, Karlsruhe, Germany
Bernhard, Christian Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland

11.10.2010

Published in:

The European Physical Journal - Special Topics. - 2010, vol. 188, no. 1, p. 73-88

English With the technique of infrared ellipsometry we performed a detailed study of the temperature- and doping dependence of the c-axis response of a series of YBa₂Cu₃O_7−δ single crystals. In particular, we explored the anomalous electronic properties at temperatures above the macroscopic superconducting transition temperature, T _c, whose conflicting explanations range from a precursor superconducting state to electronic correlations that compete with superconductivity. We show that the c-axis spectra provide evidence that both kinds of correlations are present and that their contributions can be disentangled based on an analysis with a so-called multilayer-model. We find that the onset temperature, T ^*, and the energy scale, Δ_PG, of the competing pseudogap increase rapidly towards the underdoped side whereas they vanish on the overdoped side. In addition, we provide evidence that in a strongly underdoped sample the precursor superconducting correlations develop below an onset temperature, T ^ons, that is considerably lower than T ^* but still much higher than T _c.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

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