Phase stability and physical properties of lanthanum dicarbide under pressure

ABSTRACT

First-principles calculations of electronic parameters, mechanical and dynamical stabilities on superconducting properties of the body-centered tetragonal intermetallic lanthanum dicarbide LaC₂ have been reported at zero and high pressures. The investigated properties have been established through both full-potential-linearized augmented plane wave (FP-LAPW) and plane-wave pseudopotential (PW-PP) approaches, in conjunction with the generalized gradient approximation (GGA). Our investigations validate that the LaC₂ crystal has a mechanical and dynamical stability under normal conditions. The generalised mechanical stability criteria applied to compressed LaC₂, suggest that the compound remains stable for pressures below 18.30 GPa. The evaluated superconducting critical temperature Tc and the electron–phonon coupling parameter λ at zero pressure are found to be in excellent concordance with the experimental data. Furthermore, at elevated pressures, Tc and λ are predicted to decrease and the normalised specific heat jump remains unchanged.

KEYWORDS:

• LaC₂
• electronic structure
• elastic properties
• pressure
• phonons
• superconductivity

Disclosure statement

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