2013/10/31 by Gideon Wachtel, Dror Orgad · 6 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Core (optical fiber) #Diamagnetism #Energy (signal processing) #Magnetic field #Nernst effect #Nernst equation #Order (exchange) #Phase (matter) #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Superconductivity #Thermodynamics #Vortex #Vorticity #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.90.184505
published in Physical Review B 90(18) (American Physical Society) · 9 pages, 1 figure, including supplemental material
arxiv created 2014/10/02 · openalex publication_date 2014/11/11 · arxiv updated 2015/01/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present an analytical study of diamagnetism and transport in a film with superconducting phase fluctuations, formulated in terms of vortex dynamics within the Debye-H"uckel approximation. We find that the diamagnetic and Nernst signals decay strongly with temperature in a manner that is dictated by the vortex core energy. Using the theory to interpret Nernst measurements of underdoped La_2\ensuremath-xSrxCuO4 above the critical temperature regime, we obtain a considerably better fit to the data than a fit based on Gaussian order-parameter fluctuations. Our results indicate that the core energy in this system scales roughly with the critical temperature and is significantly smaller than expected from BCS theory. Furthermore, it is necessary to assume that the vortex mobility is much larger than the Bardeen-Stephen value in order to reconcile conductivity measurements with the same vortex picture. Therefore, either the Nernst signal is not due to fluctuating vortices, or vortices in underdoped La_2\ensuremath-xSrxCuO4 have highly unconventional properties.