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Effects of electron-electron interaction in clusters of metal atoms and on the electron-pair state in a two-dimensional crystal

Grant number: 14/22092-7
Support type:Research Grants - Visiting Researcher Grant - Brazil
Duration: January 05, 2015 - February 19, 2015
Field of knowledge:Physical Sciences and Mathematics - Physics - Condensed Matter Physics
Principal Investigator:Hai Guoqiang
Grantee:Hai Guoqiang
Visiting researcher: Ladir Candido da Silva
Visiting researcher institution: Universidade Federal de Goiás (UFG). Instituto de Física, Brazil
Home Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil


During the visit of Prof. Ladir Cândido da Silva in IFSC-USP, we are going to continue the work in collaboration between our two groups in the last years. In addition to the work described in the research project about (1) the doped Au clusters and (2) the electron paring mechanism in a two-dimensional crystal, we also have some other work in collaboration to be finalized, such as the study on structural and thermodynamic properties of a graphene monolayer using path-integral Monte Carlo simulation and the bound states and non-linear screening of a donor impurity in a two-dimensional electron gas using diffusion Monte Carlo calculation. (1) About the study on doped Au clusters, we will first optimize the geometry of the Au clustersusing semi-empiric and DFT methods. Quantum Monte Carlo calculations will be performed to obtain the total energy of the cluster. We expect that we will have already obtained some reliable numerical results in the beginning of the next January such that we can start to focus on the discussions and analysis of the results in order to understanding the role of the dopant in the structural and magnetic properties of the cluster. (2) With respect to the research on the mechanism of electron paring in a 2D crystal, we are trying to calculate the self-energy of the electron pair in such a system of boson (electron pair) and fermion (single electron or hole) mixture. This calculation require the knowledge of the collective excitation spectrum in the system. In this case, we have obtained the equations for numeric calculations. We also believe that we will spend much time to discuss the possibilities on implementation of quantum Monte Carlo calculations for this problem. (AU)