Many-body perturbation theory and maximally-localized Wannier functions : a combined tool for first-principles electronic structure and quantum transport calculations
(2011)
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- Authors
- Supervisors
- Rignanese, Gian-Marco
- Abstract
- (en) Nowadays, quantum mechanic simulations are widely used to predict the properties of matter at the nanoscopic level with great accuracy. Many-body perturbation theory (MBPT), which can describe complex phenomena such as electron interactions, is amongst the most advanced techniques in this field. This methodology is, however, highly demanding in computational resources. In this manuscript, we propose a lowcost and accurate method for atomistic calculations: the combination of MBPT and maximally-localized Wannier functions (MLWFs). This effective approach is used in the calculation of excited states and transport properties of nano-materials and solids. In the field of quantum transport, experimental measurements and theoretical calculations tend to disagree for the conductance of a single molecule contacted to metallic leads. We found that many-body effects, which are missing in the most popular theoretical approaches, can partially explain this discrepancy. Second, the bandstructure of gold has been revisited. Since the 70’s, it has been observed that the theoretical prediction and the experimental measurement of the position of the electronic bands disagree. Within our approach, this long-standing disagreement has been solved. Third, we used MBPT and MLWFs to predict the electronic properties of other materials (zircon, hafnon and Ge and Si nanowires), in particular, accurate bandstructures, which can be useful in the interpretation of photo-emission experiments. The results of this thesis point to the importance of many-body effects to simulate the properties of matter at the nanoscale and to the importance of MLWFs as a cheap solution for large scale calculations.
- Affiliations
Citations
Rangel Gordillo, T. (2011). Many-body perturbation theory and maximally-localized Wannier functions : a combined tool for first-principles electronic structure and quantum transport calculations. https://hdl.handle.net/2078.5/151402