Observation of zero-dimensional states in a one-dimensional electron interferometer

Abstract

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Coulomb-Regulated Conductance Oscillations in a Disordered Quantum Wire

“…The reason is that such a dot is effectively doubly connected if the magnetic length l m is much smaller than the dot radius R, due to the presence of circulating edge states. The Aharonov-Bohm (AB) effect in such a dot may be interpreted äs resonant tunneling through zero-dimensional states [14,23]. In the absence of Coulomb interaction, the period AB of the AB oscillations for a hard-wall dot of area LW is AB -h/eLW (it may be larger for a soft-wall confining potential [14]).…”

“…The Aharonov-Bohm (AB) effect in such a dot may be interpreted äs resonant tunneling through zero-dimensional states [14,23]. In the absence of Coulomb interaction, the period AB of the AB oscillations for a hard-wall dot of area LW is AB -h/eLW (it may be larger for a soft-wall confining potential [14]). Such oscillations have indeed been observed in large quantum dots [14,15,16], but in our experiment, at high magnetic fields, no clear oscillations with the estimated AB » 0.2 T are found.…”

“…In the absence of Coulomb interaction, the period AB of the AB oscillations for a hard-wall dot of area LW is AB -h/eLW (it may be larger for a soft-wall confining potential [14]). Such oscillations have indeed been observed in large quantum dots [14,15,16], but in our experiment, at high magnetic fields, no clear oscillations with the estimated AB » 0.2 T are found. While random quantum-interference effects in the remainder of the wire and the effect of the magnetic field on the tunneling rates may be of importance, we here want to discuss the role of the electrostatic charging energy, which is dominant in small quantum dots.…”

“…This is relevant to our experiments (and to related experiments [4,5,12,13]) to the extent that one channel segment, delimited by two strong scattering centers, effectively limits the channel conductance. In addition, it is a model for experiments on the Aharonov-Bohm effect in individual quantum dots [14,15,16].…”

Sagnac interference in carbon nanotubes

“…Electron interferometry is a powerful probe of interaction effects on low-energy phases of quantum matter, as demonstrated by numerous examples. Mach-Zehnder interferometers reveal Aharonov-Bohm oscillations and quantum Hall effect edge channels, [4][5][6][7][8] and can probe exotic fractional quantum Hall states. [9][10][11] Similarly, two-path MachZehnder interferometers can probe correlated states of quantum dots.…”