Direct Chemical Fine-Tuning of Electronic Properties in Sc₂ Ir_6-x Pd_x B

Crystal orbital Hamilton population (COHP) bonding analysis has predicted that ScPd₃ B_0.5 is the least stable compound of the entire series Sc₂ Ir_6-x Pd_x B. Here, we report a systematic study of Sc₂ Ir_6-x Pd_x B (x=3, 5 and 6) by means of ¹¹ B nuclear magnetic resonance (NMR), Knight shift (K) and nuclear spin-lattice relaxation rate (1/T₁ ). NMR results combined with theoretical band structure calculations provide a measure of s- and non-s-character Fermi-level density of states. We present direct evidence that the enhanced s-state character of the Fermi level density of states (DOS) in ScPd₃ B_0.5 reduces the strength of the B 2p and Pd 4d hybridized states across the entire Sc₂ Ir_6-x Pd_x B series. This hybridization strength relates to the opening of a deep pseudogap in the density of states of Sc₂ IrPd₅ B and the chemical bonding instability of ScPd₃ B_0.5 . This study is an experimental realization of a chemical fine-tuning of the electronic properties in intermetallic perovskites.