Origin of the giant optical nonlinearity of Sb2Te3 phase change materials

We report the giant optical nonlinear absorption and refraction of Sb2Te3 phase change materials at low laser irradiation intensities. The nonlinear absorption and refraction coefficients reach up to −6.63×10−2 m/W and 2.606×10−9 m2/W, respectively. The first principles calculation indicates that the giant nonlinear absorption stems from the band filling effect of the photon induced free carriers under laser irradiation. The band-gap shrinking results in a positive thermo-optic coefficient, thus the giant nonlinear refraction. The numerical results are generally correlated with the experimental findings from z-scan and temperature-variable ellipsometric measurements.

[1]  C. T. Seaton,et al.  Band-Gap—Resonant Nonlinear Refraction in III-V Semiconductors , 1981 .

[2]  Elsa Garmire,et al.  Nonlinear Optics in Semiconductors , 1994 .

[3]  B. Jensen,et al.  Quantum theory of the dispersion of the refractive index near the fundamental absorption edge in compound semiconductors , 1983 .

[4]  E. Gornik,et al.  Physics of Narrow Gap Semiconductors , 1982 .

[5]  A. S. Malkova,et al.  The heat capacity of solid antimony telluride Sb2Te3 , 2008 .

[6]  J. Gu,et al.  Incorporation of Highly Dispersed Gold Nanoparticles into the Pore Channels of Mesoporous Silica Thin Films and their Ultrafast Nonlinear Optical Response , 2005 .

[7]  Jingsong Wei,et al.  Optical nonlinear absorption characteristics of AgInSbTe phase change thin films , 2009 .

[8]  S. Yagi,et al.  Crystallization process of Sb‐Te alloy films for optical storage , 1988 .

[9]  Fujio Izumi,et al.  VESTA: a three-dimensional visualization system for electronic and structural analysis , 2008 .

[10]  Xavier Gonze,et al.  A brief introduction to the ABINIT software package , 2005 .

[11]  Paul Mulvaney,et al.  Enhancement of third-order nonlinear optical susceptibilities in silica-capped Au nanoparticle films with very high concentrations , 2004 .

[12]  S. Smith.  Giant nonlinearities, optical bistability and the optical transistor in narrow-gap semiconductors , 1982 .

[13]  Heng Li,et al.  Optical properties of amorphous GeTe, Sb2Te3, and Ge2Sb2Te5: The role of oxygen , 2006 .

[14]  J. Zeeuwen,et al.  Recombination of hot-electrons , 1978 .

[15]  E. Kane,et al.  Band structure of indium antimonide , 1957 .

[16]  Tae-Yon Lee,et al.  Optical properties of pseudobinary GeTe, Ge 2 Sb 2 Te 5 , GeSb 2 Te 4 , GeSb 4 Te 7 , and Sb 2 Te 3 from ellipsometry and density functional theory , 2009 .

[17]  D. Miller,et al.  Room temperature excitonic nonlinear absorption and refraction in GaAs/AlGaAs multiple quantum well structures , 1984 .

[18]  B. Jensen.  Quantum theory of free carrier absorption in polar semiconductors , 1973 .

[19]  Xi Dai,et al.  Topological insulators in Bi2Se3, Bi2Te3 and Sb2Te3 with a single Dirac cone on the surface , 2009 .

[20]  S. C. Choo,et al.  Recombination Centers in InSb , 1967 .

[21]  B. Jensen,et al.  Temperature and intensity dependence of the refractive index of a compound semiconductor , 1985 .