Interface-tuning of ferroelectricity and quadruple-well state in CuInP$_2$S$_6$ via ferroelectric oxide

Kun Wang; Du Li; Jia Wang; Yifei Hao; Hailey Anderson; Li Yang; Xia Hong

doi:10.1021/acsnano.3c03567

paper

Interface-tuning of ferroelectricity and quadruple-well state in CuInP $_{2}$ S $_{6}$ via ferroelectric oxide

arXiv:2302.01504 · doi:10.1021/acsnano.3c03567

Abstract

Ferroelectric van der Waals CuInP $_{2}$ S $_{6}$ possesses intriguing quadruple-well states and negative piezoelectricity. Its technological implementation has been impeded by the relatively low Curie temperature (bulk $T_{C}$ ~42 °C) and the lack of precise domain control. Here we show that CuInP $_{2}$ S $_{6}$ can be immune to the finite size effect and exhibits enhanced ferroelectricity, piezoelectricity, and polar alignment in the ultrathin limit when interfaced with ferroelectric oxide PbZr $_{0.2}$ Ti $_{0.8}$ O $_{3}$ films. Piezoresponse force microscopy studies reveal that the polar domains in thin CuInP $_{2}$ S $_{6}$ fully conform to those of underlying PbZr $_{0.2}$ Ti $_{0.8}$ O $_{3}$ , where the piezoelectric coefficient changes sign and increases sharply with reducing thickness. High temperature $in$ $s i t u$ domain imaging points to a significantly enhanced $T_{C}$ exceeding 200 °C for 13 nm CuInP $_{2}$ S $_{6}$ on PbZr $_{0.2}$ Ti $_{0.8}$ O $_{3}$ . Density functional theory modeling and Monte Carlo simulations show that the enhanced polar alignment and $T_{C}$ can be attributed to interface-mediated structure distortion in CuInP $_{2}$ S $_{6}$ . Our study provides an effective material strategy to engineer the polar properties of CuInP $_{2}$ S $_{6}$ for flexible nanoelectronic, optoelectronic, and mechanical applications.

21 pages, 5 figures, and Supporting Information

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Disentangling stress and curvature effects in layered 2D ferroelectric CuInP2S6

Interface-tuning of ferroelectricity and quadruple-well state in CuInP2​S6​ via ferroelectric oxide

Abstract

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Cited by in corpus (1)

Interface-tuning of ferroelectricity and quadruple-well state in CuInP $_{2}$ S $_{6}$ via ferroelectric oxide