CHARACTERISATION OF STRUCTURAL, OPTICAL, ELECTRONIC, ELASTIC, DYNAMIC AND THERMODYNAMIC PROPERTIES OF B1-XALXN ALLOY BY AB-INITIO METHOD

Authors: Pashaei, P., Gültekin, A., Öztürk, M.K. and Khan, Z.

http://www.isampk.com.pk/Web/symposium.aspx

Start date: 16 October 2017

Publisher: http://www.isampk.com.pk/Web/symposium.aspx

Place of Publication: Islamabad

LDA and GGA parameters have been parameterised by Ceperley Alder, Perdev, Burke and Ernzerhof techniques and keeping the norms of conservative psedopotential in B, Al and N. CASTEP (Cambridge Sequential Total Energy Package), based on Density Function Theory was used with the help of Troullier-Martins' simulation. While in this study, structural properties of B1-xAlxNas bulk modulus, young modulus, shear modulus, Poisson's ratio, compressibility and B Gradient are calculated depending on their optical properties, electronic properties and elastic constants. For X components, the Kramers-kroning relationships were used to calculate the refractive index, absorption coefficient and energy loss function based on the dielectric constants. In addition elastic constants, bulk modulus, young modulus, shear modulus, Poisson's ratio, compressibility and B/Galan were calculated. These properties of the quaternary alloys were found by using the properties of the binary compounds. All alloys have direct band pass, showing semi-conductivity, also it is observed that the band gap decreases when the Al element is doped instead of Boron (B). It is seen that the values of the absorption coefficient, the imaginary part of the dielectric function and the values at which the extinction coefficient starts to rise are close to the band gap. It has been seen that the real part of the refractive index and the electrical constant have similar properties. Elastic constants (x = 0.25, 0.5, 0.75) were calculated for the values. For X = 0.25 and 0.75, the alloy has 6 elastic constants because it is a simple cubic structure and with 3 elastic constants it is the tetragonal structure for x = 0.5, it is found that all the alloys provide mechanical equilibrium conditions.

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