Superconductivity in Y4RuGe8 with a Vacancy-Ordered CeNiSi2-Type Superstructure
[1];
[2];
[3];
[2];
[5];
[6]
- Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Bayreuth (Germany)
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Univ. of Bayreuth (Germany); Hiroshima Univ. (Japan)
- Univ. of Colorado, Boulder, CO (United States)
- Univ. of Bayreuth (Germany)
- Argonne National Lab. (ANL), Argonne, IL (United States); Northwestern Univ., Evanston, IL (United States)
In this work, we report a new compound, Y4RuGe8, with a transition metal vacancy-ordered CeNiSi2-type superstructure, which has a superconducting transition at 1.3 K. Y4RuGe8 crystals were grown by indium flux at relatively low temperatures (below 1273 K), which makes it possible to stabilize such a vacancy-ordered phase. The crystal structure of Y4RuGe8 was solved by single-crystal X-ray diffraction and confirmed by transmission electron microscopy. The as-grown Y4RuGe8 crystals are always twinned, crystallizing in the space group $$P\bar{1}$$(no. 2) with the lattice parameters a = 5.7680(1) Å, b = 8.2042(2) Å, c = 11.5093(3) Å, α = 79.696(1)degrees, β = 88.491(1)degrees, and γ = 79.637(2)degrees; this structure is a superstructure deriving from the higher symmetry CeNiSi2-type structure (Cmcm, no. 63) due to the ordering of Ru vacancies. The ordering of Ru sites breaks slightly distorted Ge planes in the CeNiSi2 prototype into infinite cis-trans Ge chains in Y4RuGe8. The presence of bulk superconductivity in Y4RuGe8 is well supported by zero resistance and a jump in specific heat at the critical transition temperature. The Sommerfeld coefficient (19 mJ K-2 mol-1) of the specific heat is greater than that (11 mJ K-2 mol-1) estimated using the bare density of states (4.7 states/eV/f.u.) from first-principles calculations. The ab initio calculations indicate that 4d electrons of both Y and Ru and 4p electrons of Ge are the main contributors to the total density of states at the Fermi level in Y4RuGe8.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; National Science Foundation (NSF)
- Grant/Contract Number:
- AC02-06CH11357; DMR 1903888
- OSTI ID:
- 1840047
- Journal Information:
- Chemistry of Materials, Vol. 33, Issue 19; ISSN 0897-4756
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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