"Are Polarization and Magnetization Really Bulk Properties?"

Who: Raffaele Resta (University of Trieste, Italy)

Place: Donostia International Physics Center (DIPC). Manuel Lardizabal 4, Donostia

Date: Friday, 5 December 2014, 12:00

Are Polarization and Magnetization Really Bulk Properties?

Raffaele Resta
Dipartimento di Fisica,  UniversitÓ 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
2005-6 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, ?Orbital Magnetization as a Local Property?, Phys. Rev. Lett. 110, 087202

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