Strongly Correlated Material STS Calculation And Simulation

Scanning tunneling spectroscopy on a two dimensional r space, line shapes of which are different from varieties of materials and from different states on phase diagram, can be obtained by STM. Mostly it will be a peak or a gap appeared in the STS related to some bias, which indicates that some characteristic energy happens in there. So, once the STM simulation fits the line shapes of the spectroscopy, we can grasp the understanding of how the energy forms. Furthermore, the simulation work will instruct us how to proceed the STM experiment.Based on the energy band theory, the tunneling current theory of Bardeen and the Green function method, we solved the dispersion relation of a two dimensional narrow band system, gained the dI/dV feature of s-wave and d-wave superconductors and demonstrated the relation between the Green function method and STM spectroscopy. Then, we could utilize the series of methods to know electron structure of material. In the final chapter, by the methods, we studied the high temperature superconductor of cuprates, gained the quantum interference image of cuprates depended on the octet model and compared the Green function method with the Cartesian energy density method. As for the heavy fermion compounds, we accessed the Green function method to multiple band structure and quantum interference image.