Physical properties of Yb₄As₃ and related compounds

Recent experimental and theoretical works suggest that a large part of the anomalous physical properties of Yb₄As₃ arise from the magnetic excitations of one-dimensional Yb³⁺ chains produced by a charge ordering transition. To evaluate this scenario, Yb₄As₃ and other related compounds with the same anti-Th₃P₄ structure have been compared. The appearance of magnetic order in Sm₄Bi₃ and Eu₄As₃, in contrast to Yb₄As₃, is well understood based on the exchange interaction between the trivalent and divalent chains. However, in strongly Sb-doped Yb₄As₃, where the charge-ordered state is destroyed, large C/T values similar to that of pure Yb₄As₃ have been observed in the low-temperature specific heat without the existence of one-dimensional trivalent chains.