Thurs. seminar

[Cond.Matt. & Stat.Mech.Section]

CONDENSED MATTER AND STATISTICAL PHYSICS SECTION




SEMINAR on   Disorder and strong electron correlations



Thursday, 29 April      -  11:30 a.m.



Luigi Stasi Seminar Room,  Leonardo Building - first floor



Igor LUK'YANCHUK       ( University of Picardy, Amiens )



"Polarization switching in nano-scale electronics: Ginzburg-Landau  
modelling approach"



Abstract



The spontaneous polarization in ferroelectric materials could be  
expected to be completely destabilized by the backward depolarizing  
electrostatic field produced by the charge rho=div P of the  
polarization surface breakdown.  This apparent paradox is avoided by  
the segregation of the sample into polarized domains with different  
orientation of polarization, as was initially proposed by Landau and  
Kittel . This alternates the surface charge and diminishes the bulk  
depolarizing field.



To model the polarization texture in realistic samples of size of  
50-500nm we use an analytical approach solving the nonlinear Ginzburg- 
Landau equations coupled with the electrostatic equations. By  
variation of the external field we study the dynamics of polarization  
switching.  The description of the formation of domains, vortices,  
skyrmions, etc. recently seen in experiment and in first-principle  
modeling is possible.  Introducing Landau-Khalatnikov dynamics we  
study the formation and evolution of such topological textures and  
their role in polarization switching.