title: Polarization vortices in germanium telluride nanoplatelets: a theoretical study.
abstract: Using first-principles calculations based on density functional theory, we study the properties of germanium telluride crystalline nanoplatelets and nanoparticles. Above a diameter of 2.7 nm, we predict the appearance of polarization vortices giving rise to an unusual ferrotoroidic ground state with a spontaneous and reversible toroidal moment of polarization. We highlight the crucial role of inhomogeneous strain in stabilizing polarization vortices. Combined with the phase-change properties of germanium telluride, the ferrotoroidic properties could be of practical interest for ternary logic applications.
authors.affiliation: Physique Theorique des Matériaux, Université de Liège (B5), B-4000 Liège, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Durgun
authors.forename: Ph
authors.initials: P
authors.lastname: Ghosez
authors.forename: R
authors.initials: R
authors.lastname: Shaltaf
authors.forename: X
authors.initials: X
authors.lastname: Gonze
authors.forename: J-Y
authors.initials: JY
authors.lastname: Raty