High-temperature superconductivity from quantum cluster method

Trent University
date: 
mer, 12/05/2012
Français
presentation: 

 

 

High-temperature superconductors have been with us for the last 25 years, and the debate about the origin of, or mechanism for, superconductivity in these materials has been going on ever since, mainly because the answer is complicated! In the last ten years, steady progress has been made towards a better understanding of the basic model used to describe high-temperature superconductivity,  the Hubbard model. Quantum cluster methods, based on an optimal embedding of a small system (a few atoms) into an infinite lattice, tell us that the basic Physics of high-temperature superconductivity can be accounted for by the Hubbard model, and that electron pairing, at the heart of superconductivity, is very closely related to antiferromagnetic fluctuations.   
 
In the course of this presentation I will review the basics of superconductivity from a theoretical standpoint. Then I will recall the key aspects of high-temperature superconductors that differentiate them from superconducting metals and alloys. I will explain what the Hubbard model is and give a brief overview of Cluster Dynamical Mean Field Theory (a type of quantum cluster method), before  presenting numerical computations that allow us to connect electron pairing with magnetic  fluctuations.