Coexistence of superconductivity and short-range double-stripe spin correlations in Te-vapor annealed ${\mathrm{FeTe}}_{1-x}{\mathrm{Se}}_x$ ( $x\le 0.2$ )

Journal Article · 14 June 2018 · Physical Review B

DOI: https://doi.org/10.1103/PhysRevB.97.214511 · OSTI ID:1440360

Xu, Zhijun ^[1]; Schneeloch, J. A. ^[2]; Yi, Ming ^[3]; Zhao, Yang ^[4]; Matsuda, Masaaki  ^[5]; Pajerowski, Daniel M.  ^[5]; Chi, Songxue  ^[5]; Birgeneau, R. J. ^[3]; Gu, Genda ^[6]; Tranquada, John M. ^[6]; Xu, Guangyong ^[7]

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1. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). NIST Center for Neutron Research; Univ. of Maryland, College Park, MD (United States). Dept. of Materials Science and Engineering; Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
2. Brookhaven National Lab. (BNL), Upton, NY (United States). Condensed Matter Physics and Materials Science Dept.; Stony Brook Univ., NY (United States). Dept. of Physics
3. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
4. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). NIST Center for Neutron Research; Univ. of Maryland, College Park, MD (United States). Dept. of Materials Science and Engineering
5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
6. Brookhaven National Lab. (BNL), Upton, NY (United States). Condensed Matter Physics and Materials Science Dept.
7. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). NIST Center for Neutron Research; Brookhaven National Lab. (BNL), Upton, NY (United States). Condensed Matter Physics and Materials Science Dept.

In as-grown bulk crystals of Fe_1+yTe_1-xSe_x with x ≲ 0.3, excess Fe (y > 0) is inevitable and correlates with a suppression of superconductivity. At the same time, there remains the question as to whether the character of the antiferromagnetic correlations associated with the enhanced anion height above the Fe planes in Te-rich samples is compatible with superconductivity. To test this, we have annealed as-grown crystals with x = 0.1 and 0.2 in Te vapor, effectively reducing the excess Fe and inducing bulk superconductivity. Inelastic neutron scattering measurements reveal low-energy magnetic excitations consistent with short-range correlations of the double-stripe type; nevertheless, cooling into the superconducting state results in a spin gap and a spin resonance, with the extra signal in the resonance being short range with a mixed single-stripe/double-stripe character, which is different than other iron-based superconductors. In conclusion, the mixed magnetic character of these superconducting samples does not appear to be trivially explainable by inhomogeneity.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
• Grant/Contract Number: AC05-00OR22725; SC0012704; AC02-05CH1123; AC02-05CH11231
• OSTI ID: 1440360
• Alternate ID(s): OSTI ID: 1454307; OSTI ID: 1460176; OSTI ID: 1466717
• Report Number(s): BNL-205734-2018-JAAM; PRBMDO; TRN: US1901838
• Journal Information: Physical Review B, Vol. 97, Issue 21; ISSN 2469-9950
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English