Heuristic bounds on superconductivity and how to exceed them
Johannes S. Hofmann, Debanjan Chowdhury, Steven A. Kivelson, Erez Berg
Abstract
Abstract What limits the value of the superconducting transition temperature ( T c ) is a question of great fundamental and practical importance. Various heuristic upper bounds on T c have been proposed, expressed as fractions of the Fermi temperature, T F , the zero-temperature superfluid stiffness, ρ s (0), or a characteristic Debye frequency, ω 0 . We show that while these bounds are physically motivated and are certainly useful in many relevant situations, none of them serve as a fundamental bound on T c . To demonstrate this, we provide explicit models where T c / T F (with an appropriately defined T F ), T c / ρ s (0), and T c / ω 0 are unbounded.
Topics & Concepts
HeuristicSuperconductivitySuperfluidityUpper and lower boundsPhysicsFermi Gamma-ray Space TelescopeZero (linguistics)Value (mathematics)Debye modelZero temperatureCondensed matter physicsMathematicsCombinatoricsMathematical analysisMathematical optimizationStatisticsLinguisticsPhilosophyPhysics of Superconductivity and MagnetismSuperconductivity in MgB2 and AlloysHigh-pressure geophysics and materials