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Pressure-induced structural transition and huge enhancement of superconducting properties of single-crystal Fe0.99Ni0.01Se0.5Te0.5 unconventional superconductor

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Abstract

We report high-pressure structural studies (52 GPa) at room temperature combined with magnetic [(M(T):1GPa] and electrical resistivity [(ρ(T):0-21GPa)] measurements down to 2 K on Fe0.99Ni0.01Se0.5Te0.5 superconductor using designer diamond anvils (D-DAC) pressure cell. The M(T) data show huge enhancement of superconducting transition temperature (Tc) from 8.62 to 14.8 K (1 GPa) and ρ(T) reveal maximum enhancement of Tc ~ 30.5 K at 3 GPa (dTc/dP =  ~ 7.19 K/GPa) followed by moderate decrease of Tc up to 19 K at 7.5 GPa, and further increasing pressure Tc gets vanished at 10.6 GPa. The reduction of Tc due to the occurrence of structural transition that is likely associated with possible reduction of charge carriers in the density of states in Fermi surface. The high-pressure XRD measurement shows tetragonal phase exists up to 7 GPa, followed by mixed phase which is visible between 7.5 GPa and 14.5 GPa. The structural transformation occurs at 15 GPa from tetragonal (P4/nmm) to NiAs -type hexagonal phase (P63/mmc) and it is stable up to 52 GPa, confirmed from the equation of state (EOS) and it can be correlated with variation of Tc under pressure for Fe0.99Ni0.01Se0.5Te0.5 chalcogenide superconductors.

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Acknowledgments

We would like to acknowledge the support from the US National Science Foundation (NSF) under Grant No. DMR-1608682. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT operations are supported by DOE-NNSA’s Office of Experimental Sciences. The Advanced Photon Source is a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. M. Kannan and P.K. Maheshwari would like to thank CSIR for Senior Research Fellowship (SRF) and P.K.M would like to thank AcSIR for pursuing Ph.D Degree. PV acknowledges the Research Council of Norway for providing the computer time (under the Project Number NN2875k) at the Norwegian supercomputer. The author SA wishes to thank DST (SERB, ASEAN, PURSE, FIST), MHRD (RUSA, GIAN), UGC-DAE CSR (Indore), and BRNS (Mumbai) for financial support.

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  1. Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirappalli, 620024, India

    Kalaiselvan Ganesan, Govindaraj Lingannan, Kannan Murugesan & S. Arumugam

  2. Department of Physics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA

    Kalaiselvan Ganesan, Christopher S. Perreault, Gopi K. Samudrala & Yogesh K. Vohra

  3. National Physical Laboratory (CSIR), Dr. K. S. Krishnan Road, New Delhi, 110012, India

    Pankaj Kumar Maheshwari & V. P. S. Awana

  4. Department of Chemistry, Centre for Materials Science and Nanotechnology, University of Oslo, Blindern, PO Box 11126, 0318, Oslo, Norway

    Ponniah Vajeeston

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  1. Kalaiselvan Ganesan
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Ganesan, K., Lingannan, G., Murugesan, K. et al. Pressure-induced structural transition and huge enhancement of superconducting properties of single-crystal Fe0.99Ni0.01Se0.5Te0.5 unconventional superconductor. Journal of Materials Research 36, 1624–1636 (2021). https://doi.org/10.1557/s43578-021-00110-y

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