Disorder-Controlled Electrical Properties in the Ho₂Sb_1–<i>x</i>Bi_<i>x</i>O₂ Systems

Abstract

High-purity bulk samples of the Ho₂­Sb_1–<i>x</i>­Bi_<i>x</i>O₂ phases (<i>x</i> = 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 Ho₂­Sb_1–<i>x</i>­Bi_<i>x</i>O₂ system could be fully traversed without disturbing the overall <i>anti</i>-Th­Cr₂Si₂ type structure (<i>I</i>4/<i>mmm</i>). 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