Superconductivity and Structural Conversion with Na and K Doping of the Narrow-Gap Semiconductor CsBi4Te6
Year: 2018
Type: article
Abstract: The monoclinic narrow-gap (∼0.08 eV) semiconductor CsBi 4 Te 6 is a unique layered system which can be doped to achieve high thermoelectric performance as well as superconductivity. Here, we report superconductivity and structure change induced by alloying CsBi 4 Te 6 single crystals with Na and K. Substitution of Na in CsBi 4 Te 6 with doping levels ≥0.39 and of K with ≥0.63 transforms the original monoclinic structure (p-type) to the orthorhombic RbBi 3.67 Te 6 -type structure (n-type). When the K level is ≤0.18, the monoclinic structure type of CsBi 4 Te 6 is retained. Transport and magnetic measurements on all as-synthesized doped single crystals demonstrate type-II, bulk superconductivity. A maximal superconducting transition at 5.07 K, which is the highest temperature in bismuth chalcogenide-based superconductors, was obtained in Cs 0.82 K 0.18 Bi 4 Te 6 with a high upper critical field of ∼15 T. These findings suggest superconductivity may be induced by proper doping in narrow-gap semiconductors.
Source: Chemistry of Materials
Institutions: Northwestern University, Argonne National Laboratory
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, Northwestern University, Office of Science, Materials Research Science and Engineering Center, Harvard University, Division of Materials Research, Division of Electrical, Communications and Cyber Systems, Basic Energy Sciences, Argonne National Laboratory
OpenAlex ID: W2808824240