WJCMP> Vol.9 No.2, May 2019

Author(s)

Gora Dieye¹, Sameh I. Ahmed², Abdou C. Wade¹, Djibril Diop¹

¹Département de Physique, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal.
²Department of Physics, Faculty of Science, Ain Shams University, Cairo, Egypt.

Negative thermal expansion of gallium arsenide has been investigated through temperature dependent Extended X-ray Absorption Fine Structure (EXAFS) measurements. The bond thermal expansion coefficient α_bond has been evaluated and compared to negative expansion coefficient α_tens due to tension effects. The overall thermal expansion coefficient is the sum of α_bond and α_tens. Below 60 K, α_tens is greater than α_bond  yielding to a negative expansion in this temperature region. Tension effects are progressively overcome by the stretching effects in the region 60 - 300 K. The asymmetry of nearest neighbors distribution is not negligible since the gaussian approximation underestimates the bond expansion by about 0.00426 Å. This error decreases when the temperature is lowered. The accuracy in the thermal expansion evaluation and the connection between third cumulant and thermal expansion are discussed.

Negative Thermal Expansion, Tension Effects, EXAFS, Asymmetry, Gallium Arsenide

Dieye, G. , Ahmed, S. , Wade, A. and Diop, D. (2019) Evaluation of Gallium Arsenide Thermal Expansion Coefficient by Extended X-Ray Absorption Fine Structure. World Journal of Condensed Matter Physics, 9, 37-46. doi: 10.4236/wjcmp.2019.92003.