Reference : Ab initio approaches to Resonant Raman Spectroscopy of Transition Metal Dichalcogenides
Dissertations and theses : Doctoral thesis
Physical, chemical, mathematical & earth Sciences : Physics
Physics and Materials Science
Ab initio approaches to Resonant Raman Spectroscopy of Transition Metal Dichalcogenides
Pereira Coutada Miranda, Henrique mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
University of Luxembourg, ​Luxembourg, ​​Luxembourg
Docteur en Physique
Wirtz, Ludger mailto
Siebentritt, Susanne mailto
Schilling, Tanja mailto
Gonze, Xavier mailto
Giustino, Feliciano mailto
[en] Resonant Raman spectroscopy ; Transition metal dichalcogenides ; Electron-phonon interaction ; First-principles calculations ; Two-dimensional materials ; Excitonic effects
[en] This thesis deals with the theory and simulation of resonant Raman spectroscopy in two-dimensional transition metal dichalcogenides. We present two different ab initio approaches. In the first, we calculate the Raman susceptibility tensor as a function of laser energy from the change of the dielectric susceptibility with atomic displacements. In the second, we formulate the Raman tensor in terms of time-dependent perturbation theory and calculate it using electron-light and electron-phonon coupling matrix elements obtained from density functional theory. We investigate the role of resonance, quantum interference and excitonic effects in the Raman spectra of single and triple-layer MoTe2. We compare our simulations with experimental results, explaining the dependence of the Raman intensities on the excitation energy. We demonstrate that the two approaches are formally and numerically equivalent in the adiabatic limit. In addition, the second approach allows to include the dynamical effects and captures a shift of the intensities with respect to the adiabatic case. This method is also more computationally efficient and is extended to include temperature effects using many-body perturbation theory. We have implemented both of these methods in a software package with interfaces to open source ab initio codes. Furthermore, we have developed web based tools to visualize excitonic states and phonon modes.
Fonds National de la Recherche - FnR
Researchers ; Professionals ; Students ; General public
FnR ; FNR6010221 > Henrique Miranda > OTPMD > Optical And Transport Properties Of Mos2 In The Presence Of Defects > 01/10/2013 > 30/09/2017 > 2013

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