Electric polarization switching in an atomically thin binary rock salt structure
Artikel i vetenskaplig tidskrift, 2018

Inducing and controlling electric dipoles is hindered in the ultrathin limit by the finite screening length of surface charges at metal-insulator junctions 1-3, although this effect can be circumvented by specially designed interfaces 4 . Heterostructures of insulating materials hold great promise, as confirmed by perovskite oxide superlattices with compositional substitution to artificially break the structural inversion symmetry 5-8 . Bringing this concept to the ultrathin limit would substantially broaden the range of materials and functionalities that could be exploited in novel nanoscale device designs. Here, we report that non-zero electric polarization can be induced and reversed in a hysteretic manner in bilayers made of ultrathin insulators whose electric polarization cannot be switched individually. In particular, we explore the interface between ionic rock salt alkali halides such as NaCl or KBr and polar insulating Cu2N terminating bulk copper. The strong compositional asymmetry between the polar Cu2N and the vacuum gap breaks inversion symmetry in the alkali halide layer, inducing out-of-plane dipoles that are stabilized in one orientation (self-poling). The dipole orientation can be reversed by a critical electric field, producing sharp switching of the tunnel current passing through the junction.

sodium chloride

potassium bromide




Jose Martinez-Castro

Universidad de Zaragoza

University College London (UCL)

Université de Genève

Marten Piantek

Universidad de Zaragoza

Instituto de Nanociencia de Aragón

Sonja Schubert

Universidad de Zaragoza

Mats Persson

University of Liverpool

Chalmers, Fysik, Material- och ytteori

David Serrate

Instituto de Nanociencia de Aragón

Universidad de Zaragoza

C. F. Hirjibehedin

University College London (UCL)

Nature Nanotechnology

1748-3387 (ISSN)

Vol. 13 1 19-23


Fysikalisk kemi

Annan materialteknik

Den kondenserade materiens fysik



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