title: On the Chemistry and Physical Properties of Flux and Floating Zone Grown SmB6 Single Crystals.
abstract: Recent theoretical and experimental findings suggest the long-known but not well understood low temperature resistance plateau of SmB6 may originate from protected surface states arising from a topologically non-trivial bulk band structure having strong Kondo hybridization. Yet others have ascribed this feature to impurities, vacancies, and surface reconstructions. Given the typical methods used to prepare SmB6 single crystals, flux and floating-zone procedures, such ascriptions should not be taken lightly. We demonstrate how compositional variations and/or observable amounts of impurities in SmB6 crystals grown using both procedures affect the physical properties. From X-ray diffraction, neutron diffraction, and X-ray computed tomography experiments we observe that natural isotope containing (SmB6) and doubly isotope enriched ((154)Sm(11)B6) crystals prepared using aluminum flux contain co-crystallized, epitaxial aluminum. Further, a large, nearly stoichiometric crystal of SmB6 was successfully grown using the float-zone technique; upon continuing the zone melting, samarium vacancies were introduced. These samarium vacancies drastically alter the resistance and plateauing magnitude of the low temperature resistance compared to stoichiometric SmB6. These results highlight that impurities and compositional variations, even at low concentrations, must be considered when collecting/analyzing physical property data of SmB6. Finally, a more accurate samarium-154 coherent neutron scattering length, 8.9(1) fm, is reported.
authors.affiliation: Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.|Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA.|Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: W A
authors.initials: WA
authors.lastname: Phelan
authors.affiliation: Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Koohpayeh
authors.affiliation: Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.|Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA.|Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: P
authors.initials: P
authors.lastname: Cottingham
authors.affiliation: Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.|Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA.|Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Tutmaher
authors.affiliation: Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Leiner
authors.affiliation: Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Lumsden
authors.affiliation: Applied Nuclear Physics Group, Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Lavelle
authors.affiliation: Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: X P
authors.initials: XP
authors.lastname: Wang
authors.affiliation: Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: C
authors.initials: C
authors.lastname: Hoffmann
authors.affiliation: Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Siegler
authors.affiliation: Department of Physics &Astronomy and the Louisiana Consortium for Neutron Scattering, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: N
authors.initials: N
authors.lastname: Haldolaarachchige
authors.affiliation: Department of Physics &Astronomy and the Louisiana Consortium for Neutron Scattering, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: D P
authors.initials: DP
authors.lastname: Young
authors.affiliation: Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.|Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA.|Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: McQueen