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Title: Local structure and influence of bonding on the phase-change behavior of the chalcogenide compounds K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8}

Abstract

KSb{sub 5}S{sub 8} and its solid solution analogs with Rb and Tl were found to exhibit a reversible and tunable glass{sup {yields}}crystal{sup {yields}}glass phase transition. Selected members of this series were analyzed by differential scanning calorimetry to measure the effect of the substitution on the thermal properties. The solid solutions K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8} exhibited clear deviations in melting and crystallization behavior and temperatures from the parent structure. The crystallization process of the glassy KSb{sub 5}S{sub 8} as a function of temperature could clearly be followed with Raman spectroscopy. The thermal conductivity of both glassy and crystalline KSb{sub 5}S{sub 8} at room temperature is {approx}0.40 W/m K, among the lowest known values for any dense solid-state material. Electronic band structure calculations carried out on KSb{sub 5}S{sub 8} and TlSb{sub 5}S{sub 8} show the presence of large indirect band-gaps and confirm the coexistence of covalent Sb-S bonding and predominantly ionic K(Tl)...S bonding. Pair distribution function analyses based on total X-ray scattering data on both crystalline and glassy K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8} showed that the basic structure-defining unit is the same and it involves a distorted polyhedron of 'SbS{sub 7}'more » fragment of {approx}7 A diameter. The similarity of local structure between the glassy and crystalline phases accounts for the facile crystallization rate in this system. - Graphical abstract: The KSb{sub 5}S{sub 8} is a good example of a phase-change material with a mixed ionic/covalent bonding. The members of the K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8} series exhibit phase-change properties with greater glass forming ability (GFA) than KSb{sub 5}S{sub 8}. The GFA increases with increasing Rb content. In this case, the random alloy disorder in the alkali metal sublattice seems to predominate over the increased degree of ionicity in going from K...S to Rb...S bonding and works to stabilize the glass forms in K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8}.« less

Authors:
 [1];  [2];  [3];  [1];  [3];  [1];  [2];  [4];  [5];  [5];  [6]
  1. Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States)
  2. Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)
  3. Department of Physics, Central Michigan University, Mount Pleasant, MI 48859 (United States)
  4. Department of Physics, Michigan State University, East Lansing, MI 48824 (United States)
  5. Institut fuer Physikalische Chemie, Westf. Wilhelms-Universitaet Muenster (Germany)
  6. Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States), E-mail: m-kanatzidis@northwestern.edu
Publication Date:
OSTI Identifier:
21015666
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 2; Other Information: DOI: 10.1016/j.jssc.2006.10.027; PII: S0022-4596(06)00567-6; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANTIMONY COMPOUNDS; CALORIMETRY; CRYSTALLIZATION; DISTRIBUTION FUNCTIONS; GLASS; MELTING; PHASE CHANGE MATERIALS; POTASSIUM COMPOUNDS; RAMAN SPECTROSCOPY; RUBIDIUM COMPOUNDS; SODIUM COMPOUNDS; SOLID SOLUTIONS; SULFIDES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; THERMAL CONDUCTIVITY; X-RAY DIFFRACTION

Citation Formats

Wachter, J.B., Chrissafis, K., Petkov, V., Malliakas, C.D., Bilc, D., Kyratsi, Th., Paraskevopoulos, K.M., Mahanti, S.D., Torbruegge, T., Eckert, H., and Kanatzidis, M.G. Local structure and influence of bonding on the phase-change behavior of the chalcogenide compounds K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8}. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2006.10.027.
Wachter, J.B., Chrissafis, K., Petkov, V., Malliakas, C.D., Bilc, D., Kyratsi, Th., Paraskevopoulos, K.M., Mahanti, S.D., Torbruegge, T., Eckert, H., & Kanatzidis, M.G. Local structure and influence of bonding on the phase-change behavior of the chalcogenide compounds K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8}. United States. doi:10.1016/j.jssc.2006.10.027.
Wachter, J.B., Chrissafis, K., Petkov, V., Malliakas, C.D., Bilc, D., Kyratsi, Th., Paraskevopoulos, K.M., Mahanti, S.D., Torbruegge, T., Eckert, H., and Kanatzidis, M.G. Thu . "Local structure and influence of bonding on the phase-change behavior of the chalcogenide compounds K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8}". United States. doi:10.1016/j.jssc.2006.10.027.
@article{osti_21015666,
title = {Local structure and influence of bonding on the phase-change behavior of the chalcogenide compounds K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8}},
author = {Wachter, J.B. and Chrissafis, K. and Petkov, V. and Malliakas, C.D. and Bilc, D. and Kyratsi, Th. and Paraskevopoulos, K.M. and Mahanti, S.D. and Torbruegge, T. and Eckert, H. and Kanatzidis, M.G.},
abstractNote = {KSb{sub 5}S{sub 8} and its solid solution analogs with Rb and Tl were found to exhibit a reversible and tunable glass{sup {yields}}crystal{sup {yields}}glass phase transition. Selected members of this series were analyzed by differential scanning calorimetry to measure the effect of the substitution on the thermal properties. The solid solutions K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8} exhibited clear deviations in melting and crystallization behavior and temperatures from the parent structure. The crystallization process of the glassy KSb{sub 5}S{sub 8} as a function of temperature could clearly be followed with Raman spectroscopy. The thermal conductivity of both glassy and crystalline KSb{sub 5}S{sub 8} at room temperature is {approx}0.40 W/m K, among the lowest known values for any dense solid-state material. Electronic band structure calculations carried out on KSb{sub 5}S{sub 8} and TlSb{sub 5}S{sub 8} show the presence of large indirect band-gaps and confirm the coexistence of covalent Sb-S bonding and predominantly ionic K(Tl)...S bonding. Pair distribution function analyses based on total X-ray scattering data on both crystalline and glassy K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8} showed that the basic structure-defining unit is the same and it involves a distorted polyhedron of 'SbS{sub 7}' fragment of {approx}7 A diameter. The similarity of local structure between the glassy and crystalline phases accounts for the facile crystallization rate in this system. - Graphical abstract: The KSb{sub 5}S{sub 8} is a good example of a phase-change material with a mixed ionic/covalent bonding. The members of the K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8} series exhibit phase-change properties with greater glass forming ability (GFA) than KSb{sub 5}S{sub 8}. The GFA increases with increasing Rb content. In this case, the random alloy disorder in the alkali metal sublattice seems to predominate over the increased degree of ionicity in going from K...S to Rb...S bonding and works to stabilize the glass forms in K{sub 1-} {sub x} Rb {sub x} Sb{sub 5}S{sub 8}.},
doi = {10.1016/j.jssc.2006.10.027},
journal = {Journal of Solid State Chemistry},
number = 2,
volume = 180,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • The effect of substitution of up to two Te atoms by Se atoms on the crystal structure, the magnetic and electronic properties has been studied in the system Cr{sub (5+x)}Te{sub 8-y}Se{sub y}. Trigonal basic cells with space group P-3m1 for Cr{sub (1+x)}Q{sub 2} and trigonal supercells (doubling of the unit cell in all directions) with space group P-3m1 for Cr{sub (5+x)}Q{sub 8} ((1+x)=1.27, 1.32, 1.36; (5+x)=5.08, 5.28, 5.44; Q=Te, Se; Te:Se=6:2) have been identified in X-ray powder diffraction patterns and Rietveld refinements as high-temperature and low-temperature phases, respectively. The crystal structures are related to the hexagonal NiAs-type structure with metalmore » vacancies in every second metal layer. The magnetic properties are closely related to the Cr content and the structure type. Cluster-glass and spin-glass behavior at low temperatures are observed for high and low Cr contents, respectively. For the same Cr content, the phases with trigonal basic cells have higher values for the Curie temperature T{sub c} and the freezing temperature T{sub f}, and larger magnetization than those for the phases with trigonal supercells. For the same structure type, the values for T{sub c}/T{sub f} do not show a linear relationship with the change of Cr content but exhibit a V-shape fashion. Our experimental investigations were accompanied by spin-polarized relativistic Korringa-Kohn-Rostoker (SPR-KKR) electronic structure calculations. Cr deficiencies as well as atomic disorder on the chalcogen sites was accounted for using the coherent potential approximation (CPA) alloy theory. Calculation of the exchange coupling parameters J{sub ij} provided the basis for subsequent Monte Carlo simulations of the magnetic properties at finite temperatures.« less
  • The title compounds were synthesized via the high-temperature (HT) route. The materials are characterized by Rietveld analysis, magnetic measurements, and electronic band-structure calculations. Two different structural modifications depending on the synthesis conditions are observed: a HT modification with trigonal basic cells (space group: P-3m1) for Cr{sub (1+x)}Q{sub 2} ((1+x)=1.25, 1.28, 1.34, 1.37, 1.41, 1.43) and a low-temperature (LT) modification with trigonal super-cell (space group: P-3m1) for Cr{sub (5+x)}Q{sub 8} ((5+x)=5.00, 5.12, 5.36, 5.48, 5.64, 5.72). The crystal structures are closely related to the NiAs-type structure with metal vacancies in every second metal layer. The substitution of Te by Se andmore » the change of the Cr concentration induce significant alterations of the magnetic properties. With increasing Cr content the Weiss constant {theta} changes drastically from negative to strong positive values, i.e., with increasing Cr concentration a shift from predominant antiferromagnetic exchange to ferromagnetic exchange occurs. At LTs a complex magnetic behavior is observed. For some members a spin-glass (SG) behavior is found with the freezing temperature T{sub f} following the Vogel-Fulcher law. At the highest Cr concentrations ferromagnetic characteristics dominate with spontaneous magnetizations below the Curie temperatures. The differences of the magnetic properties of the LT and HT phases can be explained on the basis of interatomic distances and angles. For a deeper understanding of the experimental results, they have been compared with the results of spin polarized relativistic Korringa-Kohn-Rostoker electronic band-structure calculations and both results are consistent. To explain the features of temperature-dependent magnetization of the compounds, Monte Carlo (MC) simulations based on the Heisenberg model have been performed with the exchange coupling parameters obtained within the ab-initio calculations of the electronic structure. The possible reasons for a modification of the exchange coupling parameters responsible for the temperature-dependent features are also analyzed. - Graphical abstract: The magnetic properties of Cr{sub 1+x}Q{sub 2} and Cr{sub 5+x}Te{sub 5}Se{sub 3} (Q=Te, Se; ratio=5:3) are strongly influenced by the Cr content and the crystal structure with the Weiss constant and Curie temperature covering a large range.« less
  • A new caesium uranyl molybdate belonging to the M{sub 6}U{sub 2}Mo{sub 4}O{sub 21} family has been synthesized by solid-state reaction and its structure determined from single-crystal X-ray diffraction data. Contrary to the other alkali uranyl molybdates of this family (A=Na, K, Rb) where molybdenum atoms adopt only tetrahedral coordination and which can be formulated A{sub 6}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}], the caesium compound Cs{sub 6}U{sub 2}Mo{sub 4}O{sub 21} should be written Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] with molybdenum atoms in tetrahedral and square pyramidal environments. Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] crystallizes in the triclinic symmetry withmore » space group P1-bar and a=10.4275(14) A, b=15.075(2) A, c=17.806(2) A, {alpha}=70.72(1){sup o}, {beta}=80.38(1){sup o} and {gamma}=86.39(1){sup o}, V=2604.7(6) A{sup 3}, Z=4, {rho}{sub mes}=5.02(2) g/cm{sup 3} and {rho}{sub cal}=5.08(3) g/cm{sup 3}. A full-matrix least-squares refinement on the basis of F{sup 2} yielded R{sub 1}=0.0464 and wR{sub 2}=0.0950 for 596 parameters with 6964 independent reflections with I{>=}2{sigma}(I) collected on a BRUKER AXS diffractometer with Mo(K{alpha}) radiation and a CCD detector. The crystal structure of Cs compound is characterized by {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})]{sup 6-} parallels chains built from U{sub 2}O{sub 13} dimeric units, MoO{sub 4} tetrahedra and MoO{sub 5} square pyramids, whereas, Na, K and Rb compounds are characterized by {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}]{sup 6-} parallel chains formulated simply of U{sub 2}O{sub 13} units and MoO{sub 4} tetrahedra. Infrared spectroscopy measurements using powdered samples synthesized by solid-state reaction, confirm the structural results. The thermal stability and the electrical conductivity are also studied. The four compounds decompose at low temperature (between 540 and 610 {sup o}C). -- Graphical abstract: The staking of {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})]{sup 6-} infinite uranyl molybdate ribbons in the Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] structure. Display Omitted Highlights: {yields} Cs{sub 6}U{sub 2}Mo{sub 4}O{sub 2} a new compound with bidimensional crystal structure, characterized by infinite uranyl molybdate chains. {yields} Crystal structure similar to these of the compounds containing Na, K, Rb. {yields} Molybdenum atoms surrounded by five oxygen atoms to form an original and strongly distorted MoO{sub 5} environment. {yields} The chains arrangement illustrates the key role of the alkaline ionic radius, in the crystal structure distortion for Cs compound.« less
  • The crystal structures of two members of the solid solution series Bi{sub 6+} {sub {delta}} S{sub 6+3} {sub {delta}} Cl{sub 6-3} {sub {delta}} and of Ag{sub 1.2}Bi{sub 17.6}S{sub 23}Cl{sub 8} have been determined by single-crystal X-ray diffraction at room temperature. Single-crystals used for the investigations were obtained from a reaction involving Bi{sub 2}S{sub 3} and AgCl in the molar ratio 3:2 at 740 K. Bi{sub 6+} {sub {delta}} S{sub 6+3} {sub {delta}} Cl{sub 6-3} {sub {delta}} compounds crystallize in the hexagonal space group P6{sub 3}/m (no. 176) with a=11.427(2) A, c=4.071(1) A, for {delta}=0.64, and a=11.540(2) A, c=4.040(1) A, formore » {delta}=0.86 (Z=1). The disordered structure of Bi{sub 6+} {sub {delta}} S{sub 6+3} {sub {delta}} Cl{sub 6-3} {sub {delta}} is closely related to the ordered rhombohedral structure of Bi{sub 4}S{sub 5}Cl{sub 2}. It consists of parallel six-membered ring channels of face- and edge-sharing bicapped trigonal prisms around Bi atoms with additional Bi atoms on the central axes. Ag{sub 1.2}Bi{sub 17.6}S{sub 23}Cl{sub 8} adopts the monoclinic space group C2/m (no. 12) with a=53.036(9) A, b=4.030(1) A, c=11.643(4) A, {beta}=94.4(1){sup o}, Z=2. Ag{sub 1.2}Bi{sub 17.6}S{sub 23}Cl{sub 8} adopts a new structure type that can be interpreted as a periodic layered intergrowth of modules from Bi{sub 6+} {sub {delta}} S{sub 6+3} {sub {delta}} Cl{sub 6-3} {sub {delta}} and the pavonite homologue Ag{sub 3} {sub x} Bi{sub 5-3} {sub x} S{sub 8-6} {sub x} Cl{sub 6} {sub x} {sub -1} ({sup (2,x)}P) along [1 0 0]. The detailed geometrical analysis reveals a remarkable similarity of the interface in the three structures. - Graphical abstract: The intergrowth structure of Ag{sub 1.2}Bi{sub 17.6}S{sub 23}Cl{sub 8} highlighting the two alternating types of structural units.« less
  • The aim of the present work is to complete a preliminary study concerning the electronic band structure investigations of Na{sub x}Cu{sub 1-x}In{sub 5}S{sub 8} compounds with 0{<=}x{<=}1, which are expected to be formed at the Cu(In,Ga)Se{sub 2}/In{sub 2}S{sub 3} interface. The band structure calculations demonstrate that for the compounds containing both Na and Cu, as the Cu content increases the band gap tends to decrease, and x-ray photoemission spectroscopy measurements show that this variation is mainly due to valence-band-maximum shift along the solid solution. The band gap strongly depends on the nature of the monovalent cation, and the band structuremore » calculations demonstrate that the d electrons of copper are responsible for the shift of the valence band. In addition, it is worth noting that the Cu-containing compounds have indirect gaps.« less