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: Se6 rings and Cu2I2 dimers, which are linked in a three-dimensional framework. Cu2I2Se6 exhibits a concurrent pressure-induced metallization and superconductivity at â¼21.0 GPa with critical temperature (Tc) of â¼2.8 K. The Tc monotonically increases within the range of our study reaching â¼9.0 K around 41.0 GPa. These observations coincide with unprecedented chair-to-planar conformational changes of Se6 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 Se6 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.
Original language | English (US) |
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Pages (from-to) | 15174-15182 |
Number of pages | 9 |
Journal | Journal of the American Chemical Society |
Volume | 141 |
Issue number | 38 |
DOIs | |
State | Published - Sep 25 2019 |
Funding
The authors acknowledge Yansun Yao (University of Saskatchewan) for fruitful discussions on DFT calculations, Haozhe Liu (HPSTAR) for allowing us to use the plate DAC gearbox for helium loading, and Przemysław Dera (University of Hawaii at Manoa) for his kind demonstration of the ATREX software. We also acknowledge Z. Valy Vardeny for allowing us to use the superconducting magnet cryostat in his lab. We thank Sergy Tkachev for assistance with helium loading, Jesse Smith for tremendous experimental support, and Jared Coles and Jordan Lybarger for their help with high-pressure powder X-ray data collection. The high pressure single crystal X-ray diffraction data and powder X-ray diffraction data were collected at 13-BM-C of GeoSoilEnviroCARS (The University of Chicago, Sector 13) and at 16-ID-B of HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory, respectively. GeoSoilEnviroCARS is supported by the National Science Foundation-Earth Sciences (EAR-1634415) and Department of Energy-GeoSciences (DE-FG02-94ER14466). HPCAT operations are supported by DOE-NNSA’s Office of Experimental Sciences. Use of the COMPRES-GSECARS gas loading system and PX2 was supported by COMPRES under NSF Cooperative Agreement EAR-1661511 and by GSECARS through NSF Grant EAR-1634415 and DOE Grant DE-FG02-94ER14466. Work at Argonne (sample preparation, characterization, and crystal growth) is supported by the U.S. DOE, Office of Basic Energy Science, Materials Science and Engineering Division. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
ASJC Scopus subject areas
- Catalysis
- General Chemistry
- Biochemistry
- Colloid and Surface Chemistry
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CSD 1954498: Experimental Crystal Structure Determination
Cai, W. (Contributor), Lin, W. (Contributor), Li, L.-H. (Contributor), Malliakas, C. D. (Contributor), Zhang, R. (Contributor), Groesbeck, M. (Contributor), Bao, J.-K. (Contributor), Zhang, D. (Contributor), Sterer, E. (Contributor), Kanatzidis, M. G. (Contributor) & Deemyad, S. (Contributor), FIZ Karlsruhe - Leibniz Institute for Information Infrastructure, 2019
DOI: 10.25505/fiz.icsd.cc23ltbw, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc23ltbw&sid=DataCite
Dataset
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CSD 1954500: Experimental Crystal Structure Determination
Cai, W. (Contributor), Lin, W. (Contributor), Li, L.-H. (Contributor), Malliakas, C. D. (Contributor), Zhang, R. (Contributor), Groesbeck, M. (Contributor), Bao, J.-K. (Contributor), Zhang, D. (Contributor), Sterer, E. (Contributor), Kanatzidis, M. G. (Contributor) & Deemyad, S. (Contributor), FIZ Karlsruhe - Leibniz Institute for Information Infrastructure, 2019
DOI: 10.25505/fiz.icsd.cc23ltdy, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc23ltdy&sid=DataCite
Dataset
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CSD 1954504: Experimental Crystal Structure Determination
Cai, W. (Contributor), Lin, W. (Contributor), Li, L.-H. (Contributor), Malliakas, C. D. (Contributor), Zhang, R. (Contributor), Groesbeck, M. (Contributor), Bao, J.-K. (Contributor), Zhang, D. (Contributor), Sterer, E. (Contributor), Kanatzidis, M. G. (Contributor) & Deemyad, S. (Contributor), FIZ Karlsruhe - Leibniz Institute for Information Infrastructure, 2019
DOI: 10.25505/fiz.icsd.cc23ltj2, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc23ltj2&sid=DataCite
Dataset