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Polarization switching induced by domain wall sliding in two-dimensional ferroelectric monochalcogenides

Polarization switching induced by domain wall sliding in two-dimensional ferroelectric... The ability to switch between distinct states of polarization comprises the defining property of ferroelectrics. However, the microscopic mechanism responsible for switching is not well understood and theoretical estimates based on coherent monodomain switching typically overestimates experimentally determined coercive fields by orders of magnitude. In this work we present a detailed first principles characterization of domain walls (DWs) in two-dimensional ferroelectric GeS, GeSe, SnS and SnSe. In particular, we calculate the formation energies and migration barriers for 180∘ and 90∘ DWs, and then derive a general expression for the coercive field assuming that polarization switching is mediated by DW migration. We apply our approach to the materials studied and obtain good agreement with experimental coercive fields. The calculated coercive fields are up to two orders of magnitude smaller than those predicted from coherent monodomain switching in GeSe, SnS and SnSe. Finally, we study the optical properties of the compounds and find that the presence of 180∘ DWs leads to a significant red shift of the absorption spectrum, implying that the density of DWs may be determined by means of simple optical probes. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png 2D Materials IOP Publishing

Polarization switching induced by domain wall sliding in two-dimensional ferroelectric monochalcogenides

Petralanda, Urko; Olsen, Thomas
2D Materials , Volume 10 (1): 10 – Jan 1, 2023
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References (65)

Publisher
IOP Publishing
Copyright
© 2022 IOP Publishing Ltd
eISSN
2053-1583
DOI
10.1088/2053-1583/ac94e0
Publisher site
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Abstract

The ability to switch between distinct states of polarization comprises the defining property of ferroelectrics. However, the microscopic mechanism responsible for switching is not well understood and theoretical estimates based on coherent monodomain switching typically overestimates experimentally determined coercive fields by orders of magnitude. In this work we present a detailed first principles characterization of domain walls (DWs) in two-dimensional ferroelectric GeS, GeSe, SnS and SnSe. In particular, we calculate the formation energies and migration barriers for 180∘ and 90∘ DWs, and then derive a general expression for the coercive field assuming that polarization switching is mediated by DW migration. We apply our approach to the materials studied and obtain good agreement with experimental coercive fields. The calculated coercive fields are up to two orders of magnitude smaller than those predicted from coherent monodomain switching in GeSe, SnS and SnSe. Finally, we study the optical properties of the compounds and find that the presence of 180∘ DWs leads to a significant red shift of the absorption spectrum, implying that the density of DWs may be determined by means of simple optical probes.

Journal

2D Materials – IOP Publishing

Published: Jan 1, 2023

Keywords: two-dimensional materials; ferroelectrics; domain walls; polarization switching; light absorption; first principles calculations

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