title: Intricate short-range ordering and strongly anisotropic transport properties of Li(1-x)Sn(2+x)As₂.
abstract: A new ternary compound, Li(1-x)Sn(2+x)As2, 0.2 < x < 0.4, was synthesized via solid-state reaction of elements. The compound crystallizes in a layered structure in the R3̅m space group (No. 166) with Sn-As layers separated by layers of jointly occupied Li/Sn atoms. The Sn-As layers are comprised of Sn3As3 puckered hexagons in a chair conformation that share all edges. Li/Sn atoms in the interlayer space are surrounded by a regular As6 octahedron. Thorough investigation by synchrotron X-ray and neutron powder diffraction indicate no long-range Li/Sn ordering. In contrast, the local Li/Sn ordering was revealed by synergistic investigations via solid-state (6,7)Li NMR spectroscopy, HRTEM, STEM, and neutron and X-ray pair distribution function analyses. Due to their different chemical natures, Li and Sn atoms tend to segregate into Li-rich and Sn-rich regions, creating substantial inhomogeneity on the nanoscale. The inhomogeneous local structure has a high impact on the physical properties of the synthesized compounds: the local Li/Sn ordering and multiple nanoscale interfaces result in unexpectedly low thermal conductivity and highly anisotropic resistivity in Li(1-x)Sn(2+x)As2.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Lee
authors.forename: Derrick
authors.initials: D
authors.lastname: Kaseman
authors.forename: Sabyasachi
authors.initials: S
authors.lastname: Sen
authors.affiliation: §Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States.
authors.forename: Ivan
authors.initials: I
authors.lastname: Hung
authors.affiliation: §Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States.
authors.forename: Zhehong
authors.initials: Z
authors.lastname: Gan
authors.affiliation: ⊥Institut für Anorganische und Analytische Chemie, Universit ät Münster, Corrensstrasse 30, 48149 Münster, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Gerke
authors.affiliation: ⊥Institut für Anorganische und Analytische Chemie, Universit ät Münster, Corrensstrasse 30, 48149 Münster, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Pöttgen
authors.affiliation: ∥Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Feygenson
authors.affiliation: ∥Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
authors.forename: Jörg
authors.initials: J
authors.lastname: Neuefeind
authors.affiliation: #Laboratoire CRISMAT, UMR 6508, ENSICAEN-CNRS, Université Caen, 14050 Caen, France.
authors.forename: Oleg I
authors.initials: OI
authors.lastname: Lebedev
authors.forename: Kirill
authors.initials: K
authors.lastname: Kovnir