Polarization vortices in germanium telluride nanoplatelets: a theoretical study.
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.
Durgun
E
E
Physique Theorique des Matériaux, Université de Liège (B5), B-4000 Liège, Belgium.
Ghosez
Ph
P
Shaltaf
R
R
Gonze
X
X
Raty
J-Y
JY