Discovery of highly polarizable semiconductors BaZrS3 and Ba3Zr2S7
Author(s)
Filippone, Stephen
Zhao, Boyang
Niu, Shanyuan
Koocher, Nathan Z.
Silevitch, Daniel
Fina, Ignasi
Rondinelli, James M.
Ravichandran, Jayakanth
Jaramillo, R.
Date Issued
September 8, 2020
Journal
Physical Review Materials
Publisher
American Physical Society (APS)
Citation
Filippone, Stephen, Zhao, Boyang, Niu, Shanyuan, Koocher, Nathan Z., Silevitch, Daniel et al. 2020. "Discovery of highly polarizable semiconductors BaZrS3 and Ba3Zr2S7." Physical Review Materials, 4 (9).
Version
Final published version
Abstract
There are few known semiconductors exhibiting both strong optical response and large dielectric polarizability. Inorganic materials with large dielectric polarizability tend to be wide-band gap complex oxides. Semiconductors with a strong photoresponse to visible and infrared light tend to be weakly polarizable. Interesting exceptions to these trends are halide perovskites and phase-change chalcogenides. Here we introduce complex chalcogenides in the Ba-Zr-S system in perovskite and Ruddlesden-Popper structures as a family of highly polarizable semiconductors. We report the results of impedance spectroscopy on single crystals that establish
BaZr
S
3
and
Ba
3
Zr
2
S
7
as semiconductors with a low-frequency relative dielectric constant
ɛ
0
in the range 50–100 and band gap in the range 1.3–1.8 eV. Our electronic structure calculations indicate that the enhanced dielectric response in perovskite
BaZr
S
3
versus Ruddlesden-Popper
Ba
3
Zr
2
S
7
is primarily due to enhanced IR mode-effective charges and variations in phonon frequencies along ⟨001⟩; differences in the Born effective charges and the lattice stiffness are of secondary importance. This combination of covalent bonding in crystal structures more common to complex oxides, but comprising sulfur, results in a sizable Fröhlich coupling constant, which suggests that charge carriers are large polarons.
Subjects
Physics and Astronomy (miscellaneous)
General Materials Science
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Terms of Use
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Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/physrevmaterials.4.091601
