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UID:0-702@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20190912T110000
DTEND;TZID=Europe/Paris:20190912T120000
DTSTAMP:20190909T121553Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-excepti
 onel-du-lptms-daniel-cabra/
SUMMARY:Séminaire exceptionnel du LPTMS: Daniel Cabra - Salle des séminai
 res du FAST et du LPTMS\, bâtiment Pascal n°530 - 12 Sep 19 11:00
DESCRIPTION:Daniel Cabra (Universidad Nacional de La Plata\, Argentina)\n\n
 Multiferroics: magneto-electric coupling through phonons\n\nWe propose a m
 icroscopic magneto-electric model in which the coupling between spins and 
 electric dipoles is mediated by lattice distortions. The magnetic sector i
 s described by a spin S=1/2 Heisenberg model coupled directly to the latti
 ce via a standard spin-Peierls term and indirectly to the electric dipole 
 variables via the distortion of the surrounding electronic clouds. Electri
 c dipoles are described by Ising variables for simplicity. We show that th
 e effective magneto-electric coupling which arises due to the interconnect
 ing lattice deformations is quite efficient in one-dimensional arrays. Mor
 e precisely\, we show using bosonization and extensive DMRG numerical simu
 lations that increasing the magnetic field above the spin Peierls gap\, a 
 massive polarization switch-off occurs due to the proliferation of soliton
  pairs. We also analyze the effect of an external electric field E when th
 e magnetic system is in a gapped (plateau) phase and show that the magneti
 zation can be electrically switched between clearly distinct values. More 
 general quasi-one-dimensional models and two-dimensional systems are also 
 discussed.
CATEGORIES:seminars
LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53
 0\, rue André Riviere\, Orsay\, 91405\, France
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\
 , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST 
 et du LPTMS\, bâtiment Pascal n°530:geo:0,0
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DTSTART:20190331T030000
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