Professor Adam Kaminski
Iowa State University and Ames Laboratory

Competition between the pseudogap and superconductivity in cuprates

Pseudogap state in cuprates is one of more interesting topics in modern condensed matter physics. This state is characterized by anisotropic energy gap that leads to seemingly disconnected segments of the Fermi surface. The relationship between the pseudogap and superconductivity is one of the central issues in physics of cuprates. One of the leading theories explaining it is so called "pre-formed" pair scenario, where pseudogap is thought to be a state of paired electrons that lack the long range coherence. By studying the spectral weights associated with pseudogap and superconductivity with angle resolved photoemission spectroscopy (ARPES) we found that there is a direct correlation between the loss of the low energy spectral weight due to the opening of the pseudogap and a decrease of the spectral weight associated with superconductivity as a function of momentum and doping. We therefore conclude that the pseudogap competes with the superconductivity by depleting the spectral weight available for pairing in the region of momentum space, where the superconducting gap is largest.