The Electronic Structure of High Temperature Superconducting Material YBa2Cu3O7 under High Pressure

The electronic structure of YBa2Cu3O7 under atmosphere and 9 GPa high pressure (under which the crystal constants are contracted by 3%) are calculated, respectively. In calculation, recursion method is used and the tight binding Hamiltonian is constructed by Harrison parameters fitted to energy band. The influence of high pressure on electronic structure is discussed. The quantitative results about shift of Fermi surface, widening of energy band width and varying of atomic valence of each crystal site are given.