نویسندگان

دانشگاه صنعتی مالک اشتر اصفهان

چکیده

در کار حاضر برخی خواص فیزیکی دو تک‌بلور KTP < /span> و RTP < /span> مورد بررسی قرارگرفته است. اثر جانشانی روبیدیم بر خواص ساختاری، الکترونی و اپتیکی KTP < /span> بررسی شده است. محاسبات با استفاده از امواج تخت بهبودیافته خطی با پتانسیل کامل در چارچوب نظریه تابعی چگالی انجام‌گرفته است. خواص ساختاری با استفاده از تابعی‌های تبادلی- همبستگی متفاوت LDA، PBE، WC و PBEsol محاسبه شده است. همچنین برای محاسبه مقدار انرژی گاف تقریب PBEsol و جهت محاسبه دقیق‌تر، تقریب mBJ به کار گرفته شده است. پدیده شبه وارونی دو بلور بررسی و مقادیر آن برای هر دو بلور با استفاده از نرم‌افزار محاسبه شده است. اثر جانشانی روبیدیم بر شبه تقارن KTP < /span> و همچنین ارتباط این کمیت با خواص اپتیکی غیرخطی مورد بحث قرار گرفته است. ضرایب اپتیکی از جمله ضریب شکست، مقادیر دوشکستی و ضرایب جذب با استفاده از تابع دی‌الکتریک محاسبه گردیده، درباره وجود ناهمسانگردی در هر دو بلور بحث و نتایج مقایسه شده‌اند.

کلیدواژه‌ها

عنوان مقاله [English]

Ab- initio investigation of physical properties of KTP and RTP

نویسندگان [English]

  • Marzieh Ghoohestani
  • Ali Arab
  • Hossein Sadeghi

چکیده [English]

In this work,the physical properties of  KTP and RTP single-crystals have been investigated by performing accurate total energy calculations in the framework of density functional theory by using the full-potential linearized augmented plane wave method. The effects of Rb substitution on structural, electronic and optical properties of KTP are discussed. The structural properties have been calculated by using different exchange correlation including LDA, PBE, WC and PBEsol. Also PBEsol approximation and and more accurate approximation mBJ are employed to calculate the energy gap values. The Pseudoinversion values of both crystals have been calculated by using PseudoSymmetry software . Rb substitution effect on pseudosymmetry of KTP and also relation between second-order susceptibility of crystals and the Pseudoinversion values are discussed. The optical coefficients such as refractive index, birefringence values and absorption coefficients have been calculated by using the dielectric function. The anisotropy in the linear optical properties of KTP and RTP crystals have been demonstrated. Then calculated results have been compared.

کلیدواژه‌ها [English]

  • density functional theory -structural
  • electronic and optical properties- Pseudoinversion-dielectric function-anisotropy-birefringence
[1]. Z. Kecong and W. Ximin, Structure sensitive properties of KTP-type crystals, Chinese science bulletin 46 (2001) 2028-2036.
[2]. V. Atuchin, V. Kesler, G. Meng, and Z. Lin, The electronic structure of RbTiOPO4 and the effects of the A-site cation substitution in KTiOPO4-family crystals, Journal of Physics: Condensed Matter 24 (2012) 405503.
[3]. P. Blaha, K. Schwarz, P. Sorantin, and S. Trickey, Full-potential, linearized augmented plane wave programs for crystalline systems, Computer Physics Communications 59 (1990) 399-415.
[4]. J. P. Perdew and Y. Wang, Accurate and simple analytic representation of the electron-gas correlation energy, Physical Review B 45 (1992) 13244.
[5]. J. P. Perdew, K. Burke, and M. Ernzerhof, Generalized gradient approximation made simple, Physical review letters 77 (1996) 3865.
[6]. Z. Wu and R. E. Cohen, More accurate generalized gradient approximation for solids, Physical Review B 73 (2006) 235116.
[7]. J. P. Perdew, A. Ruzsinszky, G. I. Csonka, O. A. Vydrov, G. E. Scuseria, L. A. Constantin, X. Zhou, and K. Burke, Restoring the density-gradient expansion for exchange in solids and surfaces, Physical Review Letters 100 (2008) 136406.
[8]. F. Tran and P. Blaha, Accurate Band Gaps of Semiconductors and Insulators with a Semilocal Exchange-Correlation Potential, Physical Review Letters 102 (2009)06/03/ 226401.
[9]. D. Koller, F. Tran, and P. Blaha, Merits and limits of the modified Becke-Johnson exchange potential, Physical Review B 83 (2011)05/31/ 195134.
[10]. N. V. Somov and E. V. Chuprunov, Pseudosymmetry software for studying the pseudosymmetry of crystal atomic structures, Crystallography Reports 59 (2014)2014// 137-139.
[11]. A. H. Reshak, I. Kityk, and S. Auluck, Investigation of the linear and nonlinear optical susceptibilities of KTiOPO4 single crystals: Theory and experiment, The Journal of Physical Chemistry B 114 (2010) 16705-16712.
[12]. F. C. Zumsteg, J. D. Bierlein, and T. E. Gier, KxRb1−xTiOPO4: A new nonlinear optical material, Journal of Applied Physics 47 (1976) 4980-4985.
[13]. S. T. Norberg, J. Gustafsson, and B.-E. Mellander, Phase transitions in KTP isostructures: correlation between structure and Tc in germanium-doped RbTiOPO4, Acta Crystallographica Section B: Structural Science 59 (2003) 588-595.
[14]. N. K. Hansen, J. Protas, and G. Marnier, The electron-density distribution in KTiOPO4, Acta Crystallographica Section B: Structural Science 47 (1991) 660-672.
[15]. J. Lowther, P. Manyum, and P. Suebka, Electronic and structural properties of orthorhombic KTiOPO4 and related isomorphic materials, physica status solidi (b) 242 (2005) 1392-1398.
[16]. P. Thomas, S. Mayo, and B. Watts, Crystal structures of RbTiOAsO4, KTiO (P0. 58, As0. 42) O4, RbTiOPO4 and (Rb0. 465, K0. 535) TiOPO4, and analysis of pseudosymmetry in crystals of the KTiOPO4 family, Acta Crystallographica Section B: Structural Science 48 (1992) 401-407.
[17]. R. DeSalvo, A. A. Said, D. J. Hagan, E. W. V. Stryland, and M. Sheik-Bahae, Infrared to ultraviolet measurements of two-photon absorption and n &lt;sub&gt;2&lt;/sub&gt; in wide bandgap solids, IEEE Journal of Quantum Electronics 32 (1996) 1324-1333.
[18]. W. Ching and Y.-N. Xu, Band structure and linear optical properties of KTiOPO 4, Physical Review B 44 (1991) 5332.
[19]. H. Li, C. Kam, Y. Lam, and W. Ji, Femtosecond Z-scan measurements of nonlinear refraction in nonlinear optical crystals, Optical Materials 15 (2001) 237-242.
[20]. G. Mann and H. Weber, Measurement of Nonlinear Absorption Coefficients of KTP Crystals in the Green Spectral Range, LASER PHYSICS-LAWRENCE- 9 (1999) 426-429.
[21]. A. Zukauskas, V. Pasiskevicius, and C. Canalias, Second-harmonic generation in periodically poled bulk Rb-doped KTiOPO 4 below 400 nm at high peak-intensities, Optics express 21 (2013) 1395-1403.
[22]. N. Golego and M. Cocivera, Polycrystalline RbTiOPO 4 and KTiOPO 4 bilayer thin films by spray pyrolysis, Thin Solid Films 322 (1998) 14-20.
[23]. L. Kang, D. M. Ramo, Z. Lin, P. D. Bristowe, J. Qin, and C. Chen, First principles selection and design of mid-IR nonlinear optical halide crystals, Journal of Materials Chemistry C 1 (2013) 7363-7370.
[24]. A. Dudelzak, P.-P. Proulx, V. Denks, V. Mürk, and V. Nagirnyi, Anisotropic fundamental absorption edge of KTiOPO4 crystals, Journal of Applied Physics 87 (2000) 2110-2113.
[25]. A. P. Gazhulina and M. O. Marychev, Pseudosymmetric Features and Nonlinear Optical Properties of Potassium Titanyl Phosphate Crystals, (2013).
[26]. J. Tauc, R. Grigorovici, and A. Vancu, Optical properties and electronic structure of amorphous germanium, physica status solidi (b) 15 (1966) 627-637.

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