Theoretical study of thermoelectric properties of 2D materials
Centre for Nanosciences and Nanotechnology (C2N)
On one hand, active thermoelectric materials that can recycle wasted energy in electronic circuits must have low thermal conductivity and high electrical conductivity. Unfortunately, due to the Wiedemann Franz law, such behaviors are antonymic in common bulk materials, but should be achieved in nanostructured systems. On the other hand, for thermal management (TM) of heat in excess (to be recycled or discharged), materials having as high thermal conductivities as possible are required. The optimization of TM or TE systems based on 2D nanostructures which are smaller than the mean free path of charge and heat carriers requires an accurateunderstanding of non-equilibrium thermal transport. Thus, specific experimental setup and advanced numerical models must be designed.This internship is focused on the numerical aspects in the framework of the flagship project MACQCAQU belonging tothe NanoSaclay LABEX.However, this work will be performed in strong relationship with the experimentalists involved in the project.
Methodology and Objectives
The objective of this work is to perform a numerical study of the thermal and thermoelectric properties of several 2D materialsand theirheterostructruresby focusing on non-equilibrium transport phenomena, geometric effects and electron-phonon coupling. Among the 2D materials, layered MoS2will be studied first because it is well known in the literature, and then SnS2for its promising TE properties.First, ab-initiocalculations based on the density functional theory (DFT) will be performed to calculate the both the electron and phonon dispersions using the Quantum Espresso software. Then, phonon transport will be studied using ahomemade code based onNon Equilibirum Green’sFunction (NEGF) formalism [3, 4] using a dynamic matrix extracted from DFT. Different types of 2D nanostructures will be evaluated in terms of thermal and thermoelectric properties.
The student will acquire a broad range of skills: in solid state physics (band structure, phonon, electron quantum transport, electron-phonon interaction), technology devices, and scientific computing (DFT software) and programming (Fortran and / or C / C + +, Matlab).Besides, theresults that would be obtained during this internship could be easily published in scientific journals.This work could be a relevant preliminary step for a PhDthesis in our group.
Candidates must have a MSc in Physics, Electronics, Materials Science or related disciplines. We are seeking creative and highly motivated individuals well trained and skilled in scientific research, and available to collaborate in an interdisciplinary team. Programming experience is also desirable, but not mandatory. Please join a CV, a list of courses that you have followed and results of exams in the framework of your master program, and any other information that you judge useful.