A DFT investigation on electronic structure, charge density, mechanical stability and thermodynamic properties of XAl 3 (X ¼Sc, Yb and Lu) intermetallic compounds Ramesh Sharma a , Sajad Ahmad Dar b, * , Negeena Parveen c , Vipul Srivastava d a Department of Applied Science, Feroze Gandhi Institute of Engineering & Technology, Raebareli, 229001, Uttar Pradesh state, India b Department of Physics, Govt. Motilal Vigyan Mahavidyalya College, Bhopal, 462008, Madhya Pradesh State, India c Department of Physics, Barkatullah University, Bhopal, 462026, Madhya Pradesh State, India d Department of Physics, School of Chemical Engineering & Physical Sciences, Lovely Professional University, Phagwara, Punjab,144411, India article info Article history: Received 24 June 2019 Received in revised form 10 September 2019 Accepted 30 September 2019 Available online 1 October 2019 Keywords: XAl 3 (X ¼Sc Yb and Lu) Intermetallics Elastic Mechanical behavior thermodynamics abstract The electronic structures of AuCu 3 -type XAl 3 (X ¼ Sc, Yb, Lu) compounds have been calculated using full potential linearized augmented plane wave (FP-LAPW) method within the density functional theory. The calculations have been performed using PBE-GGA, WC-GGA and PBE-sol GGA approximations. Electronic structures in these materials confirm metallicity. Our estimated ground state properties in case of ScAl 3 are found in good agreement with the experimental values, while for YbAl 3 and LuAl 3 couldn’t be compared owing to non-existence of data. Charge density plots illustrate Sc/Yb/LueAl bonds are cova- lent, which signify according to Poisson ratio. For this reason, various elastic modulii, bulk to shear modulus ratios, Cauchy pressures were determined and it was found that XAl 3 compounds show brittle nature. Finally, specific heat capacity, Debye temperature and Grüneisen parameter under pressure (0 e15 GPa) and temperature (0e1000 K) are also elucidated using quasi harmonic model. © 2019 Elsevier Inc. All rights reserved. 1. Introduction The interest in the intermetallic compounds has been increasing since last few years because of their intricate properties and numerous scientific applications. These intermetallic compounds have their particular electronic structure making them responsible for various properties at quantum level. The intermetallic in which one of the atoms is rare-earth metal is a special class of materials, which exhibit various allotropic structures owing to valency fluc- tuation and also responsible for interesting structural, electronic and magnetic properties. Considering rare earth atom as ‘Ytter- bium’, the materials exhibit valence fluctuation, Kondo effect, or heavy fermion behavior [1]. Such kind of behavior is as a result of various parameters such as chemical environment and external pressure or temperature. This is due to the fact that in the atomic ground state, Yb shows Yb þ2 with a filled f 14 shell, but in the solid state the f -electrons may play an active role in the formation of the electronic band structure. LuAl 3 has the cubic L1 2 (AuCu 3 ) crystal structure with space group Pm3 m. Secondly, ‘Lu’ is the last element of the ‘Lanthanide series’ in the periodic Table and having filled f 14 shell. These states are found below the Femi level and mix with the conduction electron, resulting into changed electronic properties of LuAl 3 intermetallic [2]. Takegahara [3] experimental investigated YbAl 3 compound and stated about the valence transfer of Yb under pressure. Much attention has been paid to understand physical properties of Al 3 Sc compound. For example, Young’s modulus of Al 3 Sc compound was estimated by Fu et al. [4] and found to be 166 GPa under ambient conditions. In addition to that, Al 3 Sc re- ported to be brittle in nature because of strong hybridization be- tween Al-3p and Sc-4d states near the Fermi level. Secondly, optical conductivity of Al 3 Sc compound was measured by Lee et al. [5] using spectroscopic ellipsometry technique. The observed spectra of conductivity displayed two peaks centered at 2.9 eV and 4.2 eV. Further, these peaks were explained by the simulation of density of states and optical conductivity of Al 3 Sc using FP-LAPW method. Extensive studies showed that ‘pressure’ is one tool which affects various physical properties of solids [6e11]. In this context, Li. et al. [12]. have presented a study based on quasi harmonic approxi- mation and they have calculated various thermal parameters of Al 3 Mg and Al 3 Sc alloys under the effect of pressure. YbAl 3 and LuAl 3 * Corresponding author. E-mail address: sajad54453@gmail.com (S.A. Dar). Contents lists available at ScienceDirect Journal of Molecular Graphics and Modelling journal homepage: www.elsevier.com/locate/JMGM https://doi.org/10.1016/j.jmgm.2019.107463 1093-3263/© 2019 Elsevier Inc. All rights reserved. Journal of Molecular Graphics and Modelling 94 (2020) 107463