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SUMMARY:Fröhlich electron-phonon coupling from first principles: theory 
 and applications - Carla Verdi (University of Oxford)
DTSTART:20161005T100000Z
DTEND:20161005T104000Z
UID:TALK68046@talks.cam.ac.uk
CONTACT:Joseph Nelson
DESCRIPTION:Accurate ab-initio calculations of electron-phonon properties 
 in crystalline solids are still a challenging topic due to the considerabl
 e computational effort of such calculations. Additional difficulties arise
  in the case of polar materials\, where the electrons can be strongly coup
 led to the macroscopic electric field induced by optical phonons at long w
 avelength (Fröhlich coupling). In this talk I will present a method for c
 alculating the electron-phonon vertex in polar semiconductors and insulato
 rs from first principles. The formalism is a generalization of the Fröhli
 ch vertex to the case of anisotropic materials and multiple phonon branche
 s\, and can be used either as a postprocessing correction to standard elec
 tron-phonon calculations\, or in conjunction with ab initio interpolation 
 based on maximally localized Wannier functions as implemented in the EPW c
 ode. I will demonstrate this formalism by investigating the electron-phono
 n interactions in two technologically relevant materials\, anatase TiO2 an
 d the methylammonium lead halide perovskite MAPbI3.
LOCATION:TCM Seminar Room\, Cavendish Laboratory
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