Electronic properties of high-quality epitaxial topological dirac semimetal thin films

John Hellerstedt, Mark Edmonds, Navneeth Ramakrishnan, Colin Liu, Bent Weber, Anton Tadich, Kane Michael O'Donnell, Shaffique Adam, Michael Fuhrer

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39 Citations (Scopus)


Topological Dirac semimetals (TDS) are three-dimensional analogues of graphene, with linear electronic dispersions in three dimensions. Nanoscale confinement of TDSs in thin films is a necessary step toward observing the conventional-to-topological quantum phase transition (QPT) with increasing film thickness, gated devices for electric-field control of topological states, and devices with surface-state-dominated transport phenomena. Thin films can also be interfaced with superconductors (realizing a host for Majorana Fermions) or ferromagnets (realizing Weyl Fermions or T-broken topological states). Here we report structural and electrical characterization of large-area epitaxial thin films of TDS Na3Bi on single crystal Al2O3[0001] substrates. Charge carrier mobilities exceeding 6,000 cm2/(V s) and carrier densities below 1 × 1018 cm-3 are comparable to the best single crystal values. Perpendicular magnetoresistance at low field shows the perfect weak antilocalization behavior expected for Dirac Fermions in the absence of intervalley scattering. At higher fields up to 0.5 T anomalously large quadratic magnetoresistance is observed, indicating that some aspects of the low field magnetotransport (μB < 1) in this TDS are yet to be explained.

Original languageEnglish
Pages (from-to)3210-3214
Number of pages5
JournalNano Letters
Issue number5
Publication statusPublished - 11 May 2016


  • magnetotransport
  • scanning tunneling microscopy
  • thin film growth
  • Topological Dirac semimetal

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