Polarity at the nanoscale

J. Goniakowski (1) , Claudine Noguera (1)

1 INSP - Institut des Nanosciences de Paris

Relying on classical electrostatics, we extend the understanding of the electrostatic forces responsible for polarity to nano-objects. We show that while no actual divergence of the electrostatic potential occurs in polar nano-objects, beyond a critical object size, the divergent behavior of the potential differences as a function of size induces polar instability analogous to that at semi-infinite surfaces. We highlight several new and generic properties of polar nano-objects: (1) the dependence of the instability behavior on object dimensionality; (2) the driving role of the smallest structural parameter, not necessarily the thickness; (3) the inhomogeneity of the electrostatic potential within a polar termination and its divergent behavior as a function of the termination size; and (4) the polar character of symmetric stoichiometric objects with a vanishing total dipole moment. We give simple analytical arguments in order to build a generic framework, valid independent of the precise object dimensionality, structure, and ionocovalent characteristics.

Domaines: Matière Condensée [cond-mat]

J. Goniakowski, Claudine Noguera. Polarity at the nanoscale. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2011, 83 (11), pp.115413. ⟨10.1103/PhysRevB.83.115413⟩. ⟨hal-01241532⟩