Theory of multiple scattering
Theory of multiple scattering applied to spectroscopies (DS1): Theoretical description of the effective cross-section of numerous spectroscopies in which structural, electronic and magnetic information is accumulated by an electron (or several electrons) during its repeated interactions with the atoms of the material under consideration. Application in particular to systems studied by the 'Surfaces and Interfaces' research group (photoelectron diffraction, photoemission energy losses).
Development of calculation codes (DS2) : MsSpec code, interfacing the MsSpec code with ab initio electronic structure codes, calculation-experience comparison code, etc.
Theoretical description of non-equilibrium electronic transport using the Keldysh Green's function formalism. The main application of the formalism is carried out on the Ballistic Electron Emission Microscope (BEEM) in epitaxial thin films such as Au/Si, Au/GaAs and spin valves (this subject has been developed in very strong synergy with the experimental research carried out in the 'Surfaces and Interfaces' research group).
Correlated electron systems
Strongly correlated electron systems: development of model (effective) Hamiltonians, in particular super-exchange Hamiltonians or simpler ones (Heisenberg Hamiltonian, Hubbard Hamiltonian, etc.), coupled with ab-initio calculations to describe strongly correlated electron systems, local approach (fragment spectroscopy).
Ab initio study of photo-excited systems (in collaboration with the Materials and Light department): The aim of this activity is to study the photo-induced phenomena observed in pump-probe experiments. The description of non-equilibrium systems on such short time scales requires the development of specific models, parameterised by ab initio calculations (density functional).
- ‘Model dielectric functions for fluctuation potential calculations in electron gas: A critical assessment’,
Aditi Mandal, Sylvain Tricot, Rakesh Choubisa, Didier Sebilleau,
Physical Review B, 105 (19), pp.195424 (2022).
- ‘Mirror symmetry breaking in a model insulating cuprate’,
A. de La Torre, K. L. Seyler, L. Zhao, Sergio Di Matteo, M. S. Scheurer, Y. Li, B. Yu, M. Greven, S. Sachdev, M. R. Norman, D. Hsieh,
Nature Physics, 17 (7), pp.777-781 (2021).
- ‘Resonant vibration of a thin polymer film under optical excitation’,
Janine Emile, O. Emile, P. Gaudriault,
Soft Matter, 17 (14), pp.3923-3928 (2021).
- 'Screening of transition (Y, Zr, Hf, V, Nb, Mo, and Ru) and rare-earth (La and Pr) elements as potential effective dopants for thermoelectric GeTe – an experimental and theoretical appraisal',
Bhuvanesh Srinivasan, Sylvain Le Tonquesse, Alain Gellé, Cédric Bourgès, Leo Monier, Isao Ohkubo, Jean-François Halet, David Berthebaud, Takao Mori,
Journal of Materials Chemistry A, 8 (38), pp.19805-19821 (2020).