Kavli Affiliate: Joel E. Moore
| First 5 Authors: Siddhant Mal, Elizabeth J. Dresselhaus, Joel E. Moore, ,
| Summary:
Recent experiments on amorphous materials have established the existence of
surface states similar to those of crystalline three-dimensional topological
insulators (TIs). Amorphous topological insulators are also independently of
interest for thermo-electric and other properties. To develop an understanding
of transport in these systems, we carry out quantum transport calculations for
a tight-binding model of an amorphous nano-wire pierced by an axial magnetic
flux, then compare the results to known features in the case of crystalline
models with disorder. Our calculations complement previous studies in the
crystalline case that studied the surface or used a Green’s function method. We
find that the periodicity of the conductance signal with varying magnetic flux
is comparable to the crystalline case, with maxima occurring at odd multiples
of magnetic flux quanta. However, the expected amplitude of the oscillation
decreases with increasing amorphousness, as defined and described in the main
text. We characterize this deviation from the crystalline case by taking
ensemble averages of the conductance signatures for various wires with
measurements simulated at finite temperatures. This striking transport
phenomenon offers a metric to characterize amorphous TIs and stimulate further
experiments on this class of materials.
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