Discovery of highly polarizable semiconductors BaZr S3 and Ba3 Zr2 S7

Stephen Filippone, Boyang Zhao, Shanyuan Niu, Nathan Z. Koocher, Daniel Silevitch, Ignasi Fina, James M. Rondinelli, Jayakanth Ravichandran, R. Jaramillo*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


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 BaZrS3 and Ba3Zr2S7 as semiconductors with a low-frequency relative dielectric constant ɛ0 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 BaZrS3 versus Ruddlesden-Popper Ba3Zr2S7 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.

Original languageEnglish (US)
Article number091601
JournalPhysical Review Materials
Issue number9
StatePublished - Sep 2020

ASJC Scopus subject areas

  • General Materials Science
  • Physics and Astronomy (miscellaneous)


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