Pressure-Induced Superconductivity and Flattened Se6 Rings in the Wide Band Gap Semiconductor Cu2I2Se6

Weizhao Cai, Wenwen Lin, Long Hua Li, Christos D. Malliakas, Rong Zhang, Matthew Groesbeck, Jin Ke Bao, Dongzhou Zhang, Eran Sterer, Mercouri G. Kanatzidis, Shanti Deemyad*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


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 languageEnglish (US)
Pages (from-to)15174-15182
Number of pages9
JournalJournal of the American Chemical Society
Issue number38
StatePublished - Sep 25 2019

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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