Electron(hole)-phonon interaction in YBCO high temperature superconductor using quantum path integral molecular dynamics

摘要

In this research, we have implemented an original technique to study the electronic properties of a single electron placed in YBa2 at 300K. Using a discretized extension of Feynman's Quantum Path Integral, we have been able to characterize effective electron-phonon interactions, and electron location site probability. We find that the electron stabilizes at oxygen vacant sites in the copper-oxygen chains. In the copper-oxygen planes, the electron is unstable and moves into the chain. Upon complementing the quantum electron to a positive charge thereby simulating a hole, we then find that the hole moves into favorable sites in the copper-oxygen planes. These sites are surrounded by four oxygens and two copper ions. Next, by decoupling the electron and hole from the lattice, we obtain effective electron-phonon and hole-phonon coupling constants on the order of 30. These results indicate that the next area of research is to move toward a multi-electron system and allow for further study of the electrons near the Fermi level. Some of the difficulties associated with multi-electron systems such as "exchange", are briefly discussed.