Lecturer: Dr. Roni Ilan
Affiliation: University of California, Berkeley
Abstract:
Three dimensional topological insulators
(3DTI) are a vastly studied symmetry
protected topological phase. Its surface state
encloses a three dimensional bulk material and
forms a two dimensional Dirac metal with no
boundary. In this talk I will describe how this
is significant in using topological insulator
nano wires and films in order to generate,
manipulate, and detect topological effects
unique to 3DTI in transport. I will discuss our
recent theoretical works on interfaces and
junctions such as a p-n junction, a
superconducting - normal (SN) interface, and
Josephson Junctions on 3DTI nano wires, and
argue that these setups can be used to address
two outstanding challenges: the detection of
spin-momentum locking and the detection of
topological superconductivity in transport
experiments. In particular, I will argue that a
p-n junction in the quantum Hall regime forms
a Mach-Zehnder interferometer based on spin-
momentum locking, functioning as a spin-FET
with the advantage of separating spin polarized
currents on output. I will also discuss how SN
and Josephson junctions can be used in order
to detect topological superconductivity in one
dimension. For the NS junction, the
conductance developed a plateau at low
chemical potentials, and I will explain how in
the presence of a quantizing field such a
junction can be mapped onto a Majorana
interferometer. Finally I will talk about the
practical aspects of these proposed devices,
their experimental feasibility, and their
robustness to disorder and finite temperatures.