EXAFS studies of semiconductors and ferroelectrics

XAFS spectroscopy, which includes the investigations of both Extended X-ray Absorption Fine Structure (EXAFS) and X-ray absorption Near-Edge Structure (XANES), is a powerful technique for structural investigations. It is widely used in physics, materials science, chemistry (especially in catalysis and coordination chemistry), biology, geochemistry and environmental science. It can be applied to the studies of not only crystalline solids, but also to studies of various disordered, nanocrystalline, amorphous and liquid systems.

In our laboratory we use EXAFS to study the local environment of isovalent and nonisovalent impurities in narrow-gap IV-VI semiconductors with a particular emphasis to off-center impurities which can induce the ferroelectric phase transition in these crystals. We study the mechanisms in which different doping impurities influence the ferroelectric properties such as the phase transition (Curie) temperature. An interesting result of this work was the discovery of a new class of off-center ions - off-center ions of large size. Lead (Pb) and tin (Sn) impurity atoms in germanium telluride (GeTe) can serve as examples.

Our main interest now is paid to determination of the parameters of three-dimensional (3D) multiwell potential for some off-center atoms from EXAFS data. This potential is characterized by strong anharmonicity and anisotropy, so we cannot use standard approach based on the cumulant expansion method. Our approach uses exact three-dimensional integration of the atomic distribution function that is calculated within the quantum statistical approach from the wave functions obtained from numerical solution of the Schroedinger equation for 3D anharmonic anisotropic potential.

Members of the group:

• Alexander I. Lebedev
  
• Irina A. Sluchinskaya

Selected publications:

• A.I. Lebedev, I.A. Sluchinskaya, V.N. Demin and I.H. Munro. EXAFS studies of the interaction of Ge off-center atoms and impurities in GeTe. Poster presentation at the European Meeting on Ferroelectricity (EMF8) (Nijmegen, July 1995).

• A.I. Lebedev, I.A. Sluchinskaya, V.N. Demin and I.H. Munro. EXAFS studies of the influence of impurities on the phase transition in GeTe. Izv. Akad. Nauk, Ser. Fiz. 60, N 10, 46 (1996) (in Russian).

• V.V. Vavilova, Yu.K. Kovneristyi, A.I. Lebedev, V.V. Mikhailin, N.A. Palii and A.L. Rogalev. EXAFS study of Re₈₇Ta₁₃ and Re₄₈W₅₂ amorphous alloys. Dokl. Akad. Nauk 348, 197 (1996) (in Russian).

• A.I. Lebedev, I.A. Sluchinskaya, V.N. Demin and I.H. Munro. Off-centering of Pb and Sn impurities in GeTe induced by strong local stress. The 9th Int. Conf. on X-ray Absorption Fine Structure (Grenoble, August 1996), Program and Abstracts, Abstract PS3-82.

• A.I. Lebedev, I.A. Sluchinskaya, V.N. Demin and I.H. Munro. Off-centering of Pb and Sn impurities in GeTe induced by strong local stress. Pis'ma v Zh. Eksp. Teor. Fiz. 63, 600 (1996) (in Russian) [Translation: JETP Letters 63, 635 (1996)].

• A.I. Lebedev, I.A. Sluchinskaya, V.N. Demin and I.H. Munro. Off-centering of Pb and Sn impurities in GeTe. Phys. Rev. B 55, 14770 (1997); [local copy].

• A.I. Lebedev, I.A. Sluchinskaya, V.N. Demin and I.H. Munro. Influence of Se, Pb and Mn impurities on the ferroelectric phase transition in GeTe studied by EXAFS. Phase Transitions 60, 67 (1997).

• A.I. Lebedev, I.A. Sluchinskaya, V.N. Demin, I.H. Munro and G. van Dorssen. EXAFS studies of the local structure of In in PbTe, SnTe and GeTe. Daresbury Laboratory Scientific Reports 1996-97, pp. 248-249.

• A.I. Lebedev, I.A. Sluchinskaya, V.N. Demin and I.H. Munro. EXAFS studies of the local environment of lead and selenium atoms in PbTeSe solid solution. Fizika Tverdogo Tela 41, 1394 (1999) (in Russian). [Translation: Physics of the Solid State 41, 1275 (1999).]

• A.I. Lebedev, A.V. Michurin, I.A. Sluchinskaya, V.N. Demin, I. Munro. Structure and electrical properties of InTe_1-xSe_x, In_1-xGa_xTe, and In_1-xTl_xTe solid solutions. Crystallography Reports, 45, 555 (2000).

• A.I. Lebedev, A.V. Michurin, I.A. Sluchinskaya, V.N. Demin, I.H. Munro. EXAFS and electrical studies of new narrow-gap semiconductors: InTe_1-xSe_x and In_1-xGa_xTe. -- J. Phys. Chem. Solids 61, 2007 (2000); e-print arXiv:1801.00830 (2018).

• A. Lebedev, I. Sluchinskaya, I. Munro. EXAFS study of PbS-SnS solid solution. -- J. Synchr. Rad. 8, 800 (2001); [local copy].

• A.I. Lebedev, I.A. Sluchinskaya, I.H. Munro. An EXAFS study of the local structure in Pb_xSn_1-xS solid solution. -- Physics of the Solid State 44, 1643 (2002); [local copy].

• S.G. Dorofeev, A.I. Lebedev, S.G. Nikitenko, I.A. Sluchinskaya, O.I. Tananaeva. XANES determination of the charge state of thullium in PbTe. The 3d National Conf. on using of x-ray and synchrotron radiation, neutrons and electrons in materials science (Moscow, 2001). Abstract book, p. 98 (in Russian).

• A.I. Lebedev, I.A. Sluchinskaya. Direct determination of the shape of potential well for off-center Ge atom in GeTe-SnTe solid solution by EXAFS technique. 7th Russia/CIS/Baltic/Japan Symposium on Ferroelectricity (St. Petersburg, June 2002). Abstract book, p. 29.

• A.I. Lebedev, I.A. Sluchinskaya. EXAFS study of the influence of impurities on the phase transition in GeTe. -- Ferroelectrics 298, 189 (2004).

• A.I. Lebedev, I.A. Sluchinskaya. A new method for determining parameters of the potential well of off-center atoms from EXAFS data. Crystallography Reports 49, Suppl. 1, S94 (2004).

• A.I. Lebedev, I.A. Sluchinskaya, S.G. Nikitenko, S.G. Dorofeev. Determination of Tm charge state in PbTe(Tm) by XANES method. Physica Scripta T115, p. 365 (2005).

• A.A. Veligzhanin, A.I. Lebedev, V.V. Mischenko, I.A. Sluchinskaya, A.A. Chernyshov. EXAFS study of the local environment of Pb impurity in CaTiO3, SrTiO3 and BaTiO3. 5th Int. Seminar on Ferroelastic Physics (ISFP-5, Voronezh, Russia, 2006). Abstract book, p. 52.

• A.I. Lebedev, I.A. Sluchinskaya. Parameters of the potential well of an off-center Ge atom in GeTe-SnTe solid solution. -- Physics of the Solid State 49, 1132 (2007); [local copy]

• A.I. Lebedev, I.A. Sluchinskaya, A. Erko, A.A. Veligzhanin, A.A. Chernyshov. XAFS studies of the local environment of Pb impurity atoms in barium, strontium, and calcium titanates. -- Physics of the Solid State 51, 991 (2009); [local copy].

• A.I. Lebedev, I.A. Sluchinskaya, A. Erko, V.F. Kozlovskii. Direct evidence for off-centering of Mn impurity in SrTiO₃. -- JETP Letters 89, 457 (2009); [local copy].

• I.A. Sluchinskaya, A.I. Lebedev, A. Erko. Local environment and oxidation state of Mn impurity in SrTiO₃ determined from XAFS data. -- Bulletin of the Russian Academy of Sciences: Physics 74, 1235 (2010); e-print arXiv:1507.07342 (2015); [local copy].

• I.A. Sluchinskaya, A.I. Lebedev, A. Erko. XAFS studies of the local structure and charge state of the Pr impurity in SrTiO3. -- Physics of the Solid State 54, 975 (2012); [local copy].

• I.A. Sluchinskaya, A.I. Lebedev, A. Erko. Crystal structure, local structure, and defect structure of Pr-doped SrTiO₃. -- J. Appl. Phys. 112, 024103 (2012); e-print arXiv:1203.3066 (2012); [local copy].

• A.I. Lebedev, I.A. Sluchinskaya. Combined first-principles and EXAFS study of structural instability in BaZrO₃. -- J. Adv. Dielectrics 5, 1550019 (2015); e-print arXiv:1304.6359 (2013).

• I.A. Sluchinskaya, A.I. Lebedev, A. Erko. Structural position and oxidation state of nickel in SrTiO₃. -- J. Adv. Dielectrics 3, 1350031 (2013); e-print arXiv:1307.5082 (2013); [local copy].

• I.A. Sluchinskaya, A.I. Lebedev, A. Erko. Structural position and charge state of nickel in SrTiO₃. -- Physics of the Solid State 56, 449 (2014).

• M.A. Terekhin, V.N. Makhov, A.I. Lebedev, I.A. Sluchinskaya. Effect of local environment on crossluminescence kinetics in SrF2:Ba and CaF2:Ba solid solutions. -- Journal of Luminescence 166, 137 (2015); e-print arXiv:1506.02325 (2015).

• I.A. Sluchinskaya, A.I. Lebedev. An experimental and theoretical study of Ni impurity centers in Ba_0.8Sr_0.2TiO₃. -- Physics of the Solid State 59, 1512 (2017); e-print arXiv:1708.03016 (2017).

• I.A. Sluchinskaya, A.I. Lebedev. Electronic and magnetic properties of structural defects in SrTiO3(Co). -- J. Alloys and Compounds 820, 153243 (2020); e-print arXiv:1912.10711 (2019).

Other places of interest in the Internet:

• Database: publications on X-ray absorption spectroscopy (9400 references)
• The International XAFS Society
• XAFS Wiki pages