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Início
Agenda
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- 21 de novembro de 2018
16h30
Sala
18 (Cristalografia) -
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Denis
R. Candido
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IFSC
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Blurring
the boundaries between topological and non-topological phenomena
in dots
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In this work we first predict using the k.p method
and the valence band anti-crossing theory that the common III-V
InAs0.85Bi0.15/AlSb quantum well becomes a
room temperature 2D topological insulator for well thickness dc
> 6.9 nm [1]. Secondly, we analytically solve the cylindrical
InAs0.85Bi0.15 BHZ quantum dots (QDs).
Surprisingly, we find for the non-topological BHZ QDs
geometrically protected discrete helical edge states, similar to
the topological protected helical edge states within the gap in
the topological QDs [1]. We calculate the circulating currents
associated to both trivial and topological edge states and find
no substantial difference between them [1]. The two terminal
conductance calculation for two pairs of edge states as a
function of the QD radius and the gate controlling its levels
with respect to the Fermi energy of the leads shows a double
peak at 2e2/h for both topological and trivial QDs
[1]. We also show that this result does not depend on the QD
geometry, but rather on the approximate chiral symmetry of the
BHZ Hamiltonian [2] in small systems.
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[1] Denis R. Candido, Michael E. Flatté, J. Carlos
Egues - arXiv:1803.02936 - PRL in press
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[2] Denis R. Candido, M. Kharitonov, J. Carlos
Egues, Ewelina M. Hankiewicz, PRB (Rapid. Communication and
Editors' Suggestion) 98, 161111 (2018)
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