Are Polarization and Magnetization Really Bulk Properties?
DIPC Seminars
 Speaker

Raffaele Resta (University of Trieste, Italy)
 When

2014/12/05
13:00  Place
 Donostia International Physics Center (DIPC). Manuel Lardizabal 4, Donostia
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**Are Polarization and Magnetization Really Bulk Properties?**
Raffaele Resta
Dipartimento di Fisica, UniversitÃ di Trieste, Italy
Textbooks typically attempt microscopic definitions in terms of the dipole
moment per cell: this
is only correct for the spin contribution to magnetization M, but is incorrect
for both polarization
P and for the orbital contribution to M. The microscopic quantities well
defined inside a polarized material are the microscopic charge and current
densities: these trivially determine the dipole
(electric and magnetic) of a finite sample, but the sample boundary yields an
extensive contribution
to such dipoles.
Contrary to what textbooks pretend, the microscopic charge and current
densities in the bulk of a
sample do not determine the values of P and M. The problem has been solved in
1993 for P and in
20056 for M. In the latter case, there have been recent developments at the
fundamental level[1].
In this talk I will outline the state of the art about P and M.
[1] R. Bianco and R. Resta, â€œOrbital Magnetization as a Local Propertyâ€,
Phys. Rev. Lett. 110, 087202
(2013).