Structure and physical properties of YbZn2Sb2 and YbCd2Sb2

Abstract

The ternary ytterbium transition-metal antimonides YbM2Sb2 (M = Zn, Cd) were confirmed by single-crystal X-ray diffraction studies to adopt the CaAl2Si2-type structure (P 3 m1; a = 4.4424(6) Å, c = 7.4184(9) Å for YbZn2Sb2; a = 4.6512(7) Å, c = 7.5661(11) Å for YbCd2Sb2). Electrical resistivity measurements on single crystals revealed weakly metallic behaviour, with a resistivity minimum near 80 K in the case of YbCd2Sb2. The Yb atoms are predominantly divalent, as indicated by band structure calculations and X-ray photoelectron spectroscopy on YbZn2Sb2, but nonzero magnetic moments derived from magnetic susceptibility measurements and additional features in the experimental valence band spectrum provide evidence for the presence of some trivalent Yb species.