Electrostatic Modulation of the Electronic Properties of Dirac Semimetal Na3Bi
Abstract
Large-area thin films of topological Dirac semimetal Na3Bi are grown on amorphous SiO2:Si substrates to realise a field-effect transistor with the doped Si acting as back gate. As-grown films show charge carrier mobilities exceeding 7,000 cm2/Vs and carrier densities below 3 × 1018 cm-3, comparable to the best thin-film Na3Bi. An ambipolar field effect and minimum conductivity are observed, characteristic of Dirac electronic systems. The results are quantitatively understood within a model of disorder-induced charge inhomogeneity in topological Dirac semimetals. Due to the inverted band structure, the hole mobility is significantly larger than the electron mobility in Na3Bi, and when present, these holes dominate the transport properties.
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