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SUMMARY:Electron-phonon and phonon-electron coupling - Samuel Poncé\, Uni
 versité catholique de Louvain
DTSTART:20240226T143000Z
DTEND:20240226T150000Z
UID:TALK212416@talks.cam.ac.uk
CONTACT:Kang Wang
DESCRIPTION:The impact of atomic vibration on electronic properties (elect
 ron-phonon coupling) and the impact of dynamical electronic motion on the 
 atomic vibration (phonon-electron coupling) are crucial to describe many p
 henomena including carrier mobility\, phonon-assisted superconductivity\, 
 temperature dependence of the bandgaps\, electron mass enhancement\, Kohn 
 anomalies and phonon softening. The predictive calculation of these effect
 s has been made possible thanks to recent advances in perturbative first-p
 rinciples simulation of the electron-phonon coupling [1\,2].\n\nIn this pr
 esentation\, I will first discuss the Allen-Heine-Cardona theory for the r
 enormalization of the electronic bandstructure with temperature and show t
 hat the adiabatic theory breaks down in infrared-active materials [3].\n\n
 I will then present the Boltzmann transport equation within the general fr
 amework of the quantum theory of mobility [4]. I will subsequently discuss
  the accuracy limit of ab initio electron-phonon calculations of carrier m
 obilities and show that predictive calculations of electron and hole mobil
 ities require an extremely fine sampling of inelastic scattering processes
  in momentum space. Such fine sampling calculation is made possible at an 
 affordable computational cost through the use of efficient Fourier-Wannier
  interpolation of the electron-phonon matrix elements [2]. In addition\, r
 ecent advances have allowed for the extension of the theory to the realms 
 of 2D materials [5].\n\nFinally\, I will show how the phonon self-energy c
 an be efficiently and accurately used to study the fine features of Kohn a
 nomalies by using two adiabatically screened vertices due to designed erro
 r cancellation to first order [6].\n\n[1] X. Gonze et al.\, Comput. Phys. 
 Commun. 248\, 107042 (2020).\n[2] H. Lee et al.\, npj Comput. Mater. 9\, 1
 56 (2023).\n[3] S. Poncé et al.\, J. Chem. Phys. 143\, 102813 (2015).\n[4
 ] S. Poncé et al.\, Rep. Prog. Phys. 83\, 036501 (2020).\n[5] S. Poncé e
 t al.\, Phys. Rev. Lett. 130\, 166301 (2023).\n[6] J. Berges et al.\, Phys
 . Rev. X 13\, 041009 (2023).
LOCATION:Zoom link: https://zoom.us/j/92447982065?pwd=RkhaYkM5VTZPZ3pYSHpt
 UXlRSkppQT09
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