Orbital Free DFT Applied On Solids And Finite Systems And Prospects Of Jellium With Gap Kernel

In the light of recent progress of Orbital-Free Density Functional Theory (OFDFT) based on approximation of non-local (NL) Kinetic Energy Density Functionals (KEDFs), one can foresee the prospects that lies ahead in terms of computational efficiency and dealing with large scale systems. It is important to mention that, accuracy of OFDFT depends on the approximations made for KEDFs. Till now, the most accurate KEDFs are based on NL kernels constructed from the linear response theory of homogeneous electron gas (HEG). In this work, we explore beyond the HEG by employing a more general kernel based on the jellium-with-gap model (JGM).

We propose a new NL-KEDF that incorporates several new features, such as (i) having the correct low momentum(q) limit of the response function for metals and semiconductors without any modelling term, and most importantly, (iii) parameter-free. The accuracy and efficiency of the proposed JGM NL-KEDF have been demonstrated for several semiconductors and metals. The encouraging results indicate the utility and predictive power of the JGM kernel for NL KEDF developments. We also extend the JGM kernel by making it density-dependent, enabling it to effectively model localized systems such as molecular clusters. Benchmark calculations and analysis of the Pauli potential demonstrate that LJGM achieves accuracy comparable to state-of-the-art orbital-free methods, while offering improved performance for finite systems. Additionally, we calculate optical properties using our modified approach to . By enhancing the accuracy of NL-KEDFs for finite systems, our work advances nanomaterial design and a deeper understanding of nanoscale phenomena.