DFT Insights into Noble Gold-Based Compound Li5AuP2: Effect of Pressure on Physical Properties

The Department of Electrical and Electronics Engineering covers communications, signal processing, high voltage, electrical machines, power distribution systems, radar and electronic warfare, RF, electromagnetic and photonics topics. Most of the theoretical courses in our department are supported by qualified laboratory facilities. Our department has been accredited by MÜDEK since 2013. Within the scope of joint training (COOP), in-company training opportunities are offered to our students. 9 different companies train our students for one semester within the scope of joint education and provide them with work experience. The number of students participating in joint education (COOP) is increasing every year. Our students successfully completed the joint education program that started in the 2019-2020 academic year and started work after graduation. Our department, which provides pre-graduation opportunities to its students with Erasmus, joint education (COOP) and undergraduate research projects, has made an agreement with Upper Austria University of Applied Sciences (Austria) starting from this year and offers its students undergraduate (Atılım University) and master's (Upper Austria) degrees with 3+2 education program. Our department, which has the only European Remote Radio Laboratory in Foundation Universities, has a pioneering position in research (publication, project, patent).

Abstract

In this study, the Li5AuP2 compound is investigated in detail due to the unique chemical properties of gold that are different from other metals. Pressure is applied to the compound from 0 to 25 GPa to reveal its structural, mechanical, electronic, and dynamical properties using density functional theory (DFT). Within this pressure range, the compound is optimized with a tetragonal crystal structure, making it mechanically and dynam-ically stable above 18 GPa and resulting in an increment of bulk, shear, and Young's moduli of Li5AuP2. Pressure application, furthermore, changes the brittle or ductile nature of the compound. The anisotropic elastic and sound wave velocities are visualized in three dimensions. The thermal properties of the Li5AuP2 compound are obtained, including enthalpy, free energy, entropy x T, heat capacity, and Debye temperature. The electronic properties of the Li5AuP2 compound are studied using the Perdew-Burke-Ernzerhof (PBE) and Heyd-Scuseria-Ernzerhof (HSE) functionals. The pressure increment is found to result in higher band gap values. The Mulliken and bond overlap populations are also determined to reveal the chemical nature of this compound. The optical properties, such as dielectric functions, refractive index, and energy loss function of the Li5AuP2 compound, are established in detail. To our knowledge, this is the first attempt to study this compound in such detail, thus, making the results obtained here beneficial for future studies related to the chemistry of gold.

Description

SURUCU, Özge/0000-0002-8478-1267; Gencer, Aysenur/0000-0003-2574-3516; SURUCU, Gokhan/0000-0002-3910-8575; Ali, Md. Ashraf/0000-0003-4957-2192; SURUCU, Gokhan/0000-0002-3910-8575