Enhancement Effects: Theory

Abstract

The obvious desirability of obtaining superconductors with high transition temperatures has led to a great many theoretical attempts to find high transition temperature superconductors. There have been many suggestions concerning one and two dimensional superconductivity interactions which take place outside the superconducting material, ultrasonic-induced superconductivity, laser-induced superconductivity, high-magnetic-field-induced superconductivity, magnon-interaction-induced superconductivity, and more. I will restrict myself here, however, to discussing interactions which occur inside three dimensional inorganic solids under the influence of no outside fields. This will make possible a more accurate estimation of transition temperature, although transition temperatures are very difficult to calculate accurately in even the simplest actual cases. The problem of theoretically predicting effects which enhance the superconducting transition temperature is, I believe, intimately related to the problem of calculating transition temperatures of real materials, and the lack of success of many theoretical predictions of enhancement effects arises from the fact that they are often not incorporated in realistic calculations of the transition temperature. Before we can know how to change material properties to get higher transition temperatures, we must first know just how the superconducting transition temperature depends on these properties.