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Title: Pressure-induced Superconductivity and Flattened Se{sub 6} Rings in the Wide Bandgap Semiconductor Cu{sub 2}I{sub 2}Se{sub 6}.

Abstract

The two major classes of unconventional superconductors, cuprates and Fe-based superconductors, have magnetic parent compounds, are layered, and generally feature square-lattice symmetry. We report the discovery of pressure-induced superconductivity in a nonmagnetic and wide band gap 1.95 eV semiconductor, Cu2I2Se6, with a unique anisotropic structure composed of two types of distinct molecules: Se-6 rings and Cu2I2 dimers, which are linked in a three-dimensional framework. Cu2I2Se6 exhibits a concurrent pressure-induced metallization and superconductivity at similar to 21.0 GPa with critical temperature (T-c) of similar to 2.8 K. The T-c monotonically increases within the range of our study reaching similar to 9.0 K around 41.0 GPa. These observations coincide with unprecedented chair-to-planar conformational changes of Se-6 rings, an abrupt decrease along the c-axis, and negative compression within the ab plane during the phase transition. DFT calculations demonstrate that the flattened Se-6 rings within the CuSe layer create a high density of states at the Fermi level. The unique structural features of Cu2I2Se6 imply that superconductivity may emerge in anisotropic Cu-containing materials without square-lattice geometry and magnetic order in the parent compound.

Authors:
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Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
National Science Foundation (NSF); USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division
OSTI Identifier:
1571913
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 141; Journal Issue: 38
Country of Publication:
United States
Language:
English

Citation Formats

Cai, Weizhao, Lin, Wenwen, Li, Long-Hua, Malliakas, Christos D., Zhang, Rong, Groesbeck, Matthew, Bao, Jin-Ke, Zhang, Dongzhou, Sterer, Eran, Kanatzidis, Mercouri G., and Deemyad, Shanti. Pressure-induced Superconductivity and Flattened Se{sub 6} Rings in the Wide Bandgap Semiconductor Cu{sub 2}I{sub 2}Se{sub 6}.. United States: N. p., 2019. Web. doi:10.1021/jacs.9b06794.
Cai, Weizhao, Lin, Wenwen, Li, Long-Hua, Malliakas, Christos D., Zhang, Rong, Groesbeck, Matthew, Bao, Jin-Ke, Zhang, Dongzhou, Sterer, Eran, Kanatzidis, Mercouri G., & Deemyad, Shanti. Pressure-induced Superconductivity and Flattened Se{sub 6} Rings in the Wide Bandgap Semiconductor Cu{sub 2}I{sub 2}Se{sub 6}.. United States. doi:10.1021/jacs.9b06794.
Cai, Weizhao, Lin, Wenwen, Li, Long-Hua, Malliakas, Christos D., Zhang, Rong, Groesbeck, Matthew, Bao, Jin-Ke, Zhang, Dongzhou, Sterer, Eran, Kanatzidis, Mercouri G., and Deemyad, Shanti. Wed . "Pressure-induced Superconductivity and Flattened Se{sub 6} Rings in the Wide Bandgap Semiconductor Cu{sub 2}I{sub 2}Se{sub 6}.". United States. doi:10.1021/jacs.9b06794.
@article{osti_1571913,
title = {Pressure-induced Superconductivity and Flattened Se{sub 6} Rings in the Wide Bandgap Semiconductor Cu{sub 2}I{sub 2}Se{sub 6}.},
author = {Cai, Weizhao and Lin, Wenwen and Li, Long-Hua and Malliakas, Christos D. and Zhang, Rong and Groesbeck, Matthew and Bao, Jin-Ke and Zhang, Dongzhou and Sterer, Eran and Kanatzidis, Mercouri G. and Deemyad, Shanti},
abstractNote = {The two major classes of unconventional superconductors, cuprates and Fe-based superconductors, have magnetic parent compounds, are layered, and generally feature square-lattice symmetry. We report the discovery of pressure-induced superconductivity in a nonmagnetic and wide band gap 1.95 eV semiconductor, Cu2I2Se6, with a unique anisotropic structure composed of two types of distinct molecules: Se-6 rings and Cu2I2 dimers, which are linked in a three-dimensional framework. Cu2I2Se6 exhibits a concurrent pressure-induced metallization and superconductivity at similar to 21.0 GPa with critical temperature (T-c) of similar to 2.8 K. The T-c monotonically increases within the range of our study reaching similar to 9.0 K around 41.0 GPa. These observations coincide with unprecedented chair-to-planar conformational changes of Se-6 rings, an abrupt decrease along the c-axis, and negative compression within the ab plane during the phase transition. DFT calculations demonstrate that the flattened Se-6 rings within the CuSe layer create a high density of states at the Fermi level. The unique structural features of Cu2I2Se6 imply that superconductivity may emerge in anisotropic Cu-containing materials without square-lattice geometry and magnetic order in the parent compound.},
doi = {10.1021/jacs.9b06794},
journal = {Journal of the American Chemical Society},
number = 38,
volume = 141,
place = {United States},
year = {2019},
month = {9}
}