Electronic and Transport Signatures of SnTe Nanowires
T.P. Bredewoud (TU Delft - Applied Sciences)
M.T. Wimmer – Mentor (TU Delft - QRD/Wimmer Group)
S. Miles – Mentor (TU Delft - QRD/Wimmer Group)
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Abstract
Topological crystalline insulators (TCI's) are materials that host robust gapless states protected by crystalline symmetries. In this thesis, SnTe is studied using a tight-binding model. We focus on the electronic and transport properties of nanowires with (100) and (110) surface terminations, in the mesoscopic regime. In these configurations, gapless states are characterized as robust (against finite-size effects, step edges, and hinge rounding) spin-polarized surface and hinge states with corner charge, demonstrating intrinsic higher-order-topological behavior. We also investigate a mixed nanowire configuration having both (001) and (101) surface terminations, which displays extrinsic topological behavior.
Transport simulations reveal distinct conductance signatures for each surface termination. Nanowires with (100) terminations host surface states extending along the nanowire's perimeter, showing Aharonov-Bohm oscillations in longitudinal transport. Nanowires with a (110) terminations host confined surface states, giving rise to resonant tunneling conductance signatures for transverse transport.
These findings contribute to the general understanding of TCI nanowires, specifically the relationship between surface termination, gapless states, and transport signatures, providing valuable insights for the future design of TCI-based electronic devices.