Evidence for precursor superconducting pairing above Tc in underdoped cuprates from an analysis of the in-plane infrared response. (15th May 2015)

• Record Type: Journal Article
• Authors: Šopík, B; Chaloupka, J; Dubroka, A; Bernhard, C; Munzar, D
• Is Part Of: New journal of physics. Volume 17:Number 5(2015:May)
• Publication Date: 2015-05-15
• Subjects: cuprate superconductors -- infrared response -- precursor superconducting pairing above Tc; 74.25.Gz -- 74.72.-h; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/17/5/053022
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: We performed calculations of the in-plane infrared response of underdoped cuprate superconductors to clarify the origin of a characteristic dip feature which occurs in the published experimental spectra of the real part of the in-plane conductivity below an onset temperature considerably higher than . We provide several arguments, based on a detailed comparison of our results with the published experimental data, confirming that the dip feature and the related features of the memory function (a peak in M 1 and a kink in M 2 ) are due to superconducting pairing correlations that develop below . In particular, we show that (i) the dip feature, the peak and the kink of the low-temperature experimental data can be almost quantitatively reproduced by calculations based on a model of a d -wave superconductor. The formation of the dip feature in the experimental data below is shown to be analogous to the one occurring in the model spetra below . (ii) Calculations based on simple models, for which the dip in the temperature range from to is unrelated to superconducting pairing, predict a shift of the onset of the dip at the high-energy side upon entering the superconducting state, that is not observed in the experimental data; (iii) the conductivity data in conjunction with the recent photoemission data (Reber et al 2012 Nat. Phys. 8 606, Reber et al 2013 Phys. Rev. B87 060506 ) imply the persistence of the coherence factor characteristic of superconducting pairing correlations in a range of temperatures above .