Gate-Defined Tellurium Nanowire Quantum Dots

Chiral crystals of elemental Te are Weyl semiconductors with the intriguing property of combining Weyl physics with a small semiconducting band gap, which enables the creation of gate-tunable devices to probe and utilize the topological properties of Te. Specifically, the formation of gate-defined quantum dots in Te would allow Coulomb blockade spectroscopy to provide information about the strength of exchange interaction, spin-orbit coupling, and g-factors associated with discrete quantum states in Te nanostructures. This talk presents our progress in this direction using low-pressure PVD-grown Te nanowires with local control of carrier density using electrostatic gates. While atomically flat hexagonal boron nitride (hBN) gate dielectrics have been widely used for high quality layered material devices, the relatively weak adhesion to Te nanowires makes hBN-insulated Te device assembly challenging. We compare different strategies involving more traditional dielectrics, as well as a hybrid approach that uses a global Si backgate and hBN-insulated local top gates for Weyl semiconductor devices.