A new form of pseudopotential for the study of lattice mechanical properties of transition metals

ABSTRACT

The study of lattice mechanical properties of transition metals using pseudopotential is burdensome as the presence of d-band in these metals complicates their electronic structure. The use of pseudopotential for the study of physical properties can be justified if it accounts for the effect of d-band. The local form of the pseudopotentials is widely used to study the physical properties of materials due to their computational simplicity, physical transparency, and transferability to other environments. It is a well-established fact that non-local pseudopotentials should be preferred to the local ones. But, non-local pseudopotentials are proven to be at a higher computational cost. Inspired by such requirements, we, in the present communication, propose a pseudopotential comprising of one non-local (energy-dependent) and another local term in q-space. The non-local (energy-dependent) term accounts for s-p interaction, while the other term is used to account for the effect of s-d hybridisation. The Generalized Pseudopotential Theory (GPT) has been used to formulate the pseudopotential. Further, the pseudopotential has been used to study static binding energy, lattice dynamics, lattice mechanical properties and second-order elastic constants in the long-wavelength limit (q→0) for transition metals γ-Fe (fcc), Co and α-Fe (bcc). Computed results are found to be in good agreement with experimental and other theoretical results, which proves that the proposed pseudopotential itself accounts for the effect of d-band without using additional short-ranged Born–Mayer type potential and effective valency.

KEYWORDS:

• Pseudopotential
• transition metals
• lattice mechanical properties

SUBJECT CLASSIFICATION CODES:

• 63.20.D-
• 63.70.+h

Acknowledgments

We would like to dedicate this paper to one of our co-author Late Prof. (Dr.) P. R. Vyas for his valuable contribution, he was present while carrying out this research and during the time of paper submission. Authors are thankful for the computational facilities developed using financial assistance of (i) Department of Sciences and Technology (DST), New Delhi through the DST-FIST (Level 1) project (SR/FST/PSI-001/2006) (ii) University Grant Commission (UGC), New Delhi through DRS SAP (AP-I) project (F.530/10/DRS/2020), (iii) Department of Sciences and Technology (DST), New Delhi through the DST-FIST project (SR/FST/PSI-198/2014). The authors are also thankful to Dr. Priyank Kumar (Assistant professor, Department of Science & Humanities, Government Polytechnic, Dahod) for his careful observation, suggestions, and corrections to improve the readability of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).