Disorder-Controlled Electrical Properties in the Ho2Sb1–x Bi x O2 Systems

High-purity bulk samples of the Ho2­Sb1–x ­Bi x O2 phases (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared and subjected to structural and elemental analysis as well as physical property measurements. The Sb/Bi ratio in the Ho2­Sb1–x ­Bi x O2 system could be fully traversed without disturbing the overall anti-Th­Cr2Si2 type structure (I4/mmm). The single-crystal X-ray diffraction studies revealed that the local atomic displacement on the Sb/Bi site is reduced with the increasing Bi content. Such local structural perturbations lead to a gradual semiconductor-to-metal transition in the bulk materials. The significant variations in the electrical properties without a change in the charge carrier concentration are explained within the frame of the disorder-induced Anderson localization. These experimental observations demonstrated an alternative strategy for electrical properties manipulations through the control of the local atomic disorder.