Influence of atomic substitution on the superconducting critical temperature of scandium diboride: a computational study

Abstract A computational analysis utilizing Density Functional Theory (DFT) is conducted to investigate the influence of atomic substitutions on the electronic, phononic, and superconducting properties of scandium diboride (ScB 2 ). This investigation revealed significant enhancement in the material’s performance, notably through the doping of ScB 2 with gallium and copper to produce the variants ScGaB and ScCuB. These modifications resulted in a substantial increase in the critical temperature ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>C</mml:mi> </mml:mrow> </mml:msub> </mml:math> ), with the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>C</mml:mi> </mml:mrow> </mml:msub> </mml:math> of the copper-doped variant reaching up to 20.75 K. Additionally, detailed calculations of phonon dispersion relations and the density of states (DOS) along with the phonon density of states (PHDOS) were performed to evaluate the structural stability and explore the electronic hybridization between the atoms. These improvements in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>C</mml:mi> </mml:mrow> </mml:msub> </mml:math> , driven by strategic doping, represents a critical step in optimizing ScB 2 ’s properties, making it more suitable for high-impact applications in advanced technological fields.