Growth of bulk like epitaxial films of Weyl semimetal TaAs on GaAs (001)

ORAL

Abstract

Three dimensional topological semimetals (TSMs) exhibit extraordinary properties such as extremely high mobility, conductivity and magnetoresistance stemming from their protected bandstructures. They are now emerging as excellent candidates for a wide variety of applications including spintronics, thermoelectrics, and catalysts. While there has been a great deal of success studying novel bulk single crystal TSMs, they are not suitable for device applications. Thus, there is a need to develop thin film TSMs compatible with semiconductor manufacturing to accelerate the adoption of TSMs into devices. We report epitaxial growth of thick bulk-like films of Weyl semimetal TaAs on GaAs(001) substrates using molecular beam epitaxy. TaAs has been widely studied in bulk crystal form but only synthesized in thin films as ultrathin materials (10-20 nm), in which electron transport is dominated by surface states. In this presentation we discuss growth strategies to realize thick (100-300 nm) single crystal films and eliminate secondary phases. We study the electronic structure using a combination of magnetotransport and angle resolved photoemission spectroscopy. We will also discuss the impact of epitaxial growth on intrinsic doping and magnetoresistance.

*This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding for J. Nelson and TaAs epitaxy, MR characterization and TEM analysis were supported supported by the Laboratory Directed Research at Development (LDRD) Program at NREL through the Directors Fellowship. A. Rice, I. Leahy, K. Alberi, R. Kurleto, A. Shackelford, D. Dessau, and the MBE infrastructure and were supported by the U.S. Department of Energy, Office of Science of Science, Basic Energy Sciences, Physical Behavior of Materials program. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.

–

Presenters

  • Jocienne N Nelson

    • National Renewable Energy Laboratory

Authors

  • Jocienne N Nelson

    • National Renewable Energy Laboratory

  • Anthony Rice

    • National Renewable Energy Laboratory

  • Ian Leahy

    • National Renewable Energy Laboratory

  • Rafal Kurleto

    • University of Colorado, Boulder
    • Department of Physics, University of Colorado Boulder

  • John Mangum

    • National Renewable Energy Laboratory

  • Amanda Shackelford

    • University of Colorado, Boulder
    • Department of Physics, University of Colorado Boulder

  • Mark van Schilfgaarde

    • National Renewable Energy Laboratory

  • Megan Holtz

    • Colorado School of Mines

  • Dan S Dessau

    • University of Colorado, Boulder

  • Kirstin M Alberi

    • National Renewable Energy Laboratory