High Hole Mobility and Nonsaturating Giant Magnetoresistance in the New 2D Metal NaCu4Se4 Synthesized by a Unique Pathway

Haijie Chen, Joao N.B. Rodrigues, Alexander J.E. Rettie, Tze Bin Song, Daniel G. Chica, Xianli Su, Jin Ke Bao, Duck Young Chung, Wai Kwong Kwok, Lucas K. Wagner, Mercouri G Kanatzidis

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Abstract

The new compound NaCu4Se4 forms by the reaction of CuO and Cu in a molten sodium polyselenide flux, with the existence of CuO being unexpectedly critical to its synthesis. It adopts a layered hexagonal structure (space group P63/mmc with cell parameters a = 3.9931(6) Å and c = 25.167(5) Å), consisting of infinite two-dimensional [Cu4Se4]- slabs separated by Na+ cations. X-ray photoelectron spectroscopy suggests that NaCu4Se4 is mixed-valent with the formula (Na+)(Cu+)4(Se2-)(Se-)(Se2)2-. NaCu4Se4 is a p-type metal with a carrier density of â1021 cm-3 and a high hole mobility of â808 cm2 V-1 s-1 at 2 K based on electronic transport measurements. First-principles calculations suggest the density of states around the Fermi level are composed of Cu-d and Se-p orbitals. At 2 K, a very large transverse magnetoresistance of â1400% was observed, with a nonsaturating, linear dependence on field up to 9 T. Our results indicate that the use of metal oxide chemical precursors can open reaction paths to new low-dimensional compounds.

Original languageEnglish
Pages (from-to)635-642
Number of pages8
JournalJournal of the American Chemical Society
Volume141
Issue number1
DOIs
Publication statusPublished - Jan 9 2019

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ASJC Scopus subject areas

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

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