Structural stability of a golden semiconducting orthorhombic polymorph of Ti2O3 under high pressures and high temperatures

An orthorhombic polymorph of titanium oxide (Ti(2)O(3)) has been synthesized at high pressure-high temperature (HP-HT) conditions. It has been refined in the Pnma space group and the Th(2)S(3) structural type with the unit cell parameters as follows: a = 7.8248(6) Å, b = 2.8507(4) Å, c = 8.0967(3) Å, V = 180.61(1) Å(3) and Z = 4. The samples of Pnma-Ti(2)O(3) were of a golden colour, in contrast to the conventional black corundum-structured Ti(2)O(3). The structural stability of this polymorph has been examined by simultaneous Raman and x-ray diffraction studies under high pressure over 70 GPa and high temperature over 2200 K. No phase transformations or chemical reactions have been established. The electrical resistivity of Th(2)S(3)-structured Ti(2)O(3) samples showed a semiconducting behaviour and, at ambient conditions, was equal to 0.20-0.46 Ω cm. Conventional near-infrared absorption spectroscopy established the absence of energy gaps above 0.25 eV.

[1]  Jinwang Li,et al.  High‐Pressure Synthesis of Tantalum Nitride Having Orthorhombic U2S3 Structure , 2009 .

[2]  L. Dubrovinsky,et al.  Nanocrystalline diamond synthesized from C60 , 2005 .

[3]  R. Jeanloz,et al.  Raman spectroscopy and x-ray diffraction of phase transitions in Cr 2 O 3 to 61 GPa , 2004 .

[4]  L. Dubrovinsky,et al.  Iron-carbon interactions at high temperatures and pressures , 2008 .

[5]  D. Rubie,et al.  A new large-volume multianvil system , 2004 .

[6]  S. V. Ovsyannikov,et al.  Thermoelectric properties and phase transitions of II–VI semiconductors at high pressure , 2007 .

[7]  R. Wentzcovitch,et al.  Prediction of an U2S3-type polymorph of Al2O3 at 3.7 Mbar , 2008, Proceedings of the National Academy of Sciences.

[8]  G. Zou,et al.  High-pressure x-ray diffraction and Raman spectra study of indium oxide , 2008 .

[9]  R. J. Sladek,et al.  Elastic Constants and the Electrical Transition in Ti 2 O 3 , 1973 .

[10]  P. M. Raccah,et al.  Raman Study of the Semiconductor-Metal Transition in Ti 2 O 3 , 1971 .

[11]  R. Wentzcovitch,et al.  Multi-Mbar Phase Transitions in Minerals , 2010 .

[12]  R. Haange,et al.  Structure of two modifications of dysprosium sesquisulfide, Dy2S3 , 1991 .

[13]  Cui Qiliang,et al.  High-Pressure and High-Temperature Behaviour of Gallium Oxide , 2008 .

[14]  W. Zachariasen.  Crystal chemical studies of the 5f-series of elements. X. Sulfides and oxysulfides , 1949 .

[15]  S. Ono,et al.  In situ X-ray observation of phase transformation in Fe2O3 at high pressures and high temperatures , 2005 .

[16]  Mario Valle,et al.  Transparent dense sodium , 2009, Nature.

[17]  Y. Ohishi,et al.  High-pressure phase transition to the Gd(2)S(3) structure in Sc(2)O(3): a new trend in dense structures in sesquioxides. , 2009, Inorganic chemistry.

[18]  A. Gurlo,et al.  High‐pressure high‐temperature synthesis of Rh2O3‐II‐type In2O3 polymorph , 2008 .

[19]  A. Oganov,et al.  Theoretical and experimental evidence for a post-perovskite phase of MgSiO3 in Earth's D″ layer , 2004, Nature.

[20]  S. Shin,et al.  Thermoelectric Effects in Pure and V-Doped Ti 2 O 3 Single Crystals , 1973 .

[21]  F. H. Kruse,et al.  The crystal structure of antimony selenide, Sb2Se3 , 1957 .

[22]  I. Yahia,et al.  Transport properties of polycrystalline TiO2 and Ti2O3 as semiconducting oxides , 2008 .

[23]  Robert Nemanich,et al.  Interference-enhanced raman scattering of very thin titanium and titanium oxide films , 1980 .

[24]  E. Makovicky,et al.  Equation of state and crystal structure of Sb2S3 between 0 and 10 GPa , 2003 .

[25]  L. Mattheiss.  Electronic structure of rhombohedral , 1996 .

[26]  A. Oganov,et al.  Stability and compressibility of the high-pressure phases of Al2O3 up to 200 GPa: Implications for the electrical conductivity of the base of the lower mantle , 2006 .

[27]  N. Mott.  Metal-insulator transition in Ti2O3 , 1981 .

[28]  E. Makovicky,et al.  Crystal structure and cation lone electron pair activity of Bi2S3 between 0 and 10 GPa , 2005 .

[29]  T. Hartmann,et al.  Equation of state of gallium oxide to 70 GPa: Comparison of quasihydrostatic and nonhydrostatic compression , 2008 .

[30]  Masatoshi Imada,et al.  Metal-insulator transitions , 1998 .

[31]  Gang Chen,et al.  Thermoelectric property studies on bulk TiOx with x from 1 to 2 , 2007 .

[32]  T. Kikegawa,et al.  High-pressure behavior of β-Ga2O3 nanocrystals , 2010 .

[33]  H. Frederikse,et al.  Electrical Conduction inp-Type Titanium Sesquioxide , 1961 .

[34]  W. R. Robinson,et al.  High‐temperature crystal chemistry of Ti2O3: structural changes accompanying the semiconductor–metal transition , 1977 .

[35]  R. Bradt,et al.  Thermal expansion of corundum structure Ti2O3 and V2O3 , 1973 .

[36]  A. Gurlo,et al.  Metastability of corundum-type In2O3. , 2008, Chemistry.

[37]  J. M. Honig,et al.  Electrical Properties ofTi2O3Single Crystals , 1968 .

[38]  Artem R Oganov,et al.  The high-pressure phase of alumina and implications for Earth's D'' layer. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[39]  Yanming Ma,et al.  High-pressure structural transitions of Sc2O3 by X-ray diffraction, Raman spectra, and ab initio calculations. , 2009, Inorganic chemistry.

[40]  T. Kikegawa,et al.  High-pressure phase transition of hematite, Fe2O3 , 2004 .

[41]  F. J. Morin,et al.  Oxides Which Show a Metal-to-Insulator Transition at the Neel Temperature , 1959 .

[42]  Taku Okada,et al.  A new high-pressure polymorph of Ti2O3: implication for high-pressure phase transition in sesquioxides , 2009 .

[43]  L. Dubrovinsky,et al.  A novel gas-loading system for mechanically closing of various types of diamond anvil cells. , 2008, The Review of scientific instruments.

[44]  L. Dubrovinsky,et al.  High-pressure behavior of perovskite: FeTiO_{3} dissociation into (Fe_{1-delta},Ti_{delta})O and Fe_{1+delta}Ti_{2-delta}O_{5}. , 2009, Physical review letters.

[45]  Y. Ohishi,et al.  Post-Perovskite Phase Transition in MgSiO3 , 2004, Science.

[46]  S. V. Ovsyannikov,et al.  Galvanomagnetic properties of fast neutron bombarded Fe3O4 magnetite: A case against charge ordering mechanism of the Verwey transition , 2009 .

[47]  Katsuya Shimizu,et al.  Direct observation of a pressure-induced metal-to-semiconductor transition in lithium , 2009, Nature.

[48]  L. Dubrovinsky,et al.  Portable laser-heating system for diamond anvil cells. , 2009, Journal of synchrotron radiation.

[49]  Razvan Caracas,et al.  Post-perovskite phase in selected sesquioxides from density-functional calculations , 2007 .

[50]  J. Tsuchiya,et al.  Post- Rh 2 O 3 ( II ) transition and the high pressure-temperature phase diagram of gallia: A first-principles and x-ray diffraction study , 2007 .