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Vortex‐Oriented Ferroelectric Domains in SnTe/PbTe Monolayer Lateral Heterostructures
Author(s) -
Chang Kai,
Villanova John W. D.,
Ji JingRong,
Das Souvik,
Küster Felix,
BarrazaLopez Salvador,
Sessi Paolo,
Parkin Stuart S. P.
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202102267
Subject(s) - ferroelectricity , heterojunction , materials science , monolayer , condensed matter physics , polarization (electrochemistry) , epitaxy , vortex , quantum tunnelling , piezoresponse force microscopy , dielectric , nanotechnology , optoelectronics , physics , chemistry , layer (electronics) , thermodynamics
Heterostructures formed from interfaces between materials with complementary properties often display unconventional physics. Of especial interest are heterostructures formed with ferroelectric materials. These are mostly formed by combining thin layers in vertical stacks. Here the first in situ molecular beam epitaxial growth and scanning tunneling microscopy characterization of atomically sharp lateral heterostructures between a ferroelectric SnTe monolayer and a paraelectric PbTe monolayer are reported. The bias voltage dependence of the apparent heights of SnTe and PbTe monolayers, which are closely related to the type‐II band alignment of the heterostructure, is investigated. Remarkably, it is discovered that the ferroelectric domains in the SnTe surrounding a PbTe core form either clockwise or counterclockwise vortex‐oriented quadrant configurations. In addition, when there is a finite angle between the polarization and the interface, the perpendicular component of the polarization always points from SnTe to PbTe. Supported by first‐principles calculation, the mechanism of vortex formation and preferred polarization direction is identified in the interaction between the polarization, the space charge, and the strain effect at the horizontal heterointerface. The studies bring the application of 2D group‐IV monochalcogenides on in‐plane ferroelectric heterostructures a step closer.