Synthesis, Crystal and Electronic Structures, and Magnetic and Electrical Transport Properties of Bismuthides NdZn_0.6Bi₂ and (La_0.5RE_0.5)Zn_0.6Bi₂ (RE = Pr or Nd)

Bismuth is a good constituent element for many quantum materials due to its large atomic number, 6s²6p³ orbitals, and strong spin-orbital coupling. In this work, three new bismuthides, NdZn_0.6Bi₂, (La_0.5Pr_0.5)Zn_0.6Bi₂, and (La_0.5Nd_0.5)Zn_0.6Bi₂, were grown by a metal flux method, and their crystal structures were accurately determined by single-crystal X-ray diffraction. These new bismuthides belong to the RE-T-Pn₂ (RE = La-Lu, T = Mn, Fe, Co, Ni, or Zn, and Pn = P, As, Sb, or Bi) family, are isostructural, and crystallize in the HfCuSi₂ structure type. The bismuth elements have two possible oxidation states, Bi^3- and Bi^-, which were studied by X-ray photoelectron spectroscopy (XPS). Two binding energy peaks of 155.91 and 161.23 eV were observed for Bi atoms within NdZn_0.6Bi₂, and similar binding energy peaks were detected in NdBi and LiBi. XPS also confirmed the trivalent nature of Nd, which was further verified by magnetic measurements. Additionally, magnetic measurements revealed that NdZn_0.6Bi₂ exhibits an antiferromagnetic transition around 3 K, while the mixed-cation compounds do not show any magnetic transition down to 2 K. Electronic transport measurements reveal weak magnetoresistance in all three compounds, with a maximum value of ∼25% at 2 K and 9 T for (La_0.5Nd_0.5)Zn_0.6Bi₂.