Abstract
Electric-field tunable indirect-to-direct band gap transitions occur in thin-film silicon and transition metal dichalcogenides; however, they remain challenging to access in three-dimensional transition metal oxides. Very recently, an unusual polar-to-nonpolar phase transition under epitaxial strain was discovered in A3B2O7 hybrid improper ferroelectrics (HIFs), which supports controllable dielectric anisotropy and magnetization. Here we examine HIF (ABO3)1/(A′BO3)1 superlattices and AA′BB′O6 double perovskites and predict a competing nonpolar antiferroelectric phase, demonstrating it is hidden in hybrid improper ferroelectrics exhibiting corner-connected BO6 octahedra. Furthermore, we show the transition between the polar and nonpolar phases enables an in-plane electric field to control the indirect-to-direct band gap transition at the phase boundary in the (ABO3)1/(A′BO3)1 superlattices and AA′BB′O6 double perovskites, which may be tuned through static strain or chemical substitution. Our findings establish HIFs as a functional electronics class from which to realize direct gap materials and enables the integration of a broader palette of chemistries and compounds for linear and nonlinear optical applications.
Original language | English (US) |
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Article number | 054409 |
Journal | Physical Review Materials |
Volume | 2 |
Issue number | 5 |
DOIs | |
State | Published - May 17 2018 |
Funding
We thank Prof. Hongjun Xiang for support of the genetic algorithm structure search code. X.-Z.L. thanks Dr. Hongwei Wang for the helpful discussion in the Wannier90 calculations. X.-Z.L. and J.M.R. were supported by the National Science Foundation (NSF) through the Pennsylvania State University MRSEC under Award No. DMR-1420620. DFT calculations were performed on the CARBON cluster at the Center for Nanoscale Materials [Argonne National Laboratory, supported by DOE-BES (Grant No. DE-AC02-06CH11357)], the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by NSF (Grant No. ACI-1548562), and the DoD Supercomputing Resource Centers supported by the High Performance Computing and Modernization Program of the DoD.
ASJC Scopus subject areas
- General Materials Science
- Physics and Astronomy (miscellaneous)