Effective two-dimensional thickness for the Berezinskii-Kosterlitz-Thouless-like transition in a highly underdopedLa2−xSrxCuO4

Baity, P.G. , Shi, X., Shi, Z., Benfatto, L. and Popović, D. (2016) Effective two-dimensional thickness for the Berezinskii-Kosterlitz-Thouless-like transition in a highly underdopedLa2−xSrxCuO4. Physical Review B, 93(2), 024519. (doi: 10.1103/physrevb.93.024519)

Abstract

The nature of the superconducting transition in highly underdoped thick films of La 2 − x Sr x CuO 4 ( x = 0.07 and 0.08) has been investigated using the in-plane transport measurements. The contribution of superconducting fluctuations to the conductivity in zero magnetic field, or paraconductivity, was determined from the magnetoresistance measured in fields applied perpendicular to the CuO 2 planes. Both the temperature dependence of the paraconductivity above the transition and the nonlinear current-voltage ( I − V ) characteristics measured across it exhibit the main signatures of the Berezinskii-Kosterlitz-Thouless (BKT) transition. The quantitative comparison of the superfluid stiffness, extracted from the I − V data, with the renormalization-group results for the BKT theory, reveals a large value of the vortex-core energy. This finding is confirmed by the analysis of the paraconductivity obtained using different methods. The results strongly suggest that the characteristic energy scale controlling the BKT behavior in this layered system corresponds to the superfluid stiffness of a few layers.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Baity, Dr Paul
• Authors: Baity, P.G., Shi, X., Shi, Z., Benfatto, L., and Popović, D.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Physical Review B
• Publisher: American Physical Society
• ISSN: 1098-0121
• ISSN (Online): 1550-235X
• Published Online: 25 January 2016