Phase‐Dependent Superconductivity in LnB 2 C 2 (Ln = Y, Lu and La) and Prediction of Y 2 B
Hosea Sichula, Sadık Baǧcı, Hüseyin Yasin Uzunok, H. M. TütüncüABSTRACT
This work reports first‐principles studies of structural, electronic, elastic, mechanical, phononic and electron–phonon interaction properties for the simple tetragonal P4/mbm and P4 2 /mmc structures of (Ln = Y, Lu, and La) in comparison with a base‐centered orthorhombic Cmmm structure of . Extensive analysis establishes both the mechanical and dynamical stability of all studied compounds, evidenced by detailed calculations of elastic constants and phonon dispersion spectra. Calculated Vickers hardness values reach up to 18.77 GPa, identifying as a promising candidate for wear‐resistant coatings and cutting tools. The study further evaluates the polycrystalline bulk modulus, shear modulus, Young's modulus and Poisson's ratio, demonstrating significant anisotropy in these systems. Electronic structure calculations show that all the studied compounds are electrically conductive, and the contribution to the electrical conductivity comes from Ln d electrons as well as p electrons of B and C atoms. Finally, electron–phonon interaction calculations reveal for the first time that is a weakly coupled superconductor with a transition temperature of 1.25 K and a small electron–phonon coupling parameter of 0.429. Overall, the study provides the microscopic mechanisms governing mechanical and superconducting properties of and .