Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userAharonov-Bohm oscillations in the vortex dynamics in superconducting hollow cylinders
119
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Using time-dependent Ginzburg-Landau theory we demonstrate that the Aharonov-Bohm (AB) effect, resulting from a Berry phase shift of the (macroscopic) wavefunction, is revealed through the dynamics of topological phase defects present in that same wavefunction. We study vortices and antivortices on the surface of a hollow superconducting cylinder, moving on circular orbits as they are subjected to the force from the current flowing parallel to the cylinder axis. Due to the AB effect the orbit deflections, caused by a magnetic field component along the cylinder axis, become periodic as a function of field, leading to strong and robust resistance oscillations.
rate research
Read More
A direct signature of electron transport at the metallic surface of a topological insulator is the Aharonov-Bohm oscillation observed in a recent study of Bi_2Se_3 nanowires [Peng et al., Nature Mater. 9, 225 (2010)] where conductance was found to oscillate as a function of magnetic flux $phi$ through the wire, with a period of one flux quantum $phi_0=h/e$ and maximum conductance at zero flux. This seemingly agrees neither with diffusive theory, which would predict a period of half a flux quantum, nor with ballistic theory, which in the simplest form predicts a period of $phi_0$ but a minimum at zero flux due to a nontrivial Berry phase in topological insulators. We show how h/e and h/2e flux oscillations of the conductance depend on doping and disorder strength, provide a possible explanation for the experiments, and discuss further experiments that could verify the theory.
Experimental study of quantum Hall corrals reveals Aharonov-Bohm-Like (ABL) oscillations. Unlike the Aharonov-Bohm effect which has a period of one flux quantum, $Phi_{0}$, the ABL oscillations possess a flux period of $Phi_{0}/f$, where $f$ is the integer number of fully filled Landau levels in the constrictions. Detection of the ABL oscillations is limited to the low magnetic field side of the $ u_{c}$ = 1, 2, 4, 6... integer quantum Hall plateaus. These oscillations can be understood within the Coulomb blockade model of quantum Hall interferometers as forward tunneling and backscattering, respectively, through the center island of the corral from the bulk and the edge states. The evidence for quantum interference is weak and circumstantial.
We investigate transport in the network of valley Hall states that emerges in minimally twisted bilayer graphene under interlayer bias. To this aim, we construct a scattering theory that captures the network physics. In the absence of forward scattering, symmetries constrain the network model to a single parameter that interpolates between one-dimensional chiral zigzag modes and pseudo-Landau levels. Moreover, we show how the coupling of zigzag modes affects magnetotransport. In particular, we find that scattering between parallel zigzag channels gives rise to Aharonov-Bohm oscillations that are robust against temperature, while coupling between zigzag modes propagating in different directions leads to Shubnikov-de Haas oscillations that are smeared out at finite temperature.
We show that transport and thermodynamic properties of emph{singly-connected} disordered conductors exhibit quantum Aharonov - Bohm oscillations with the total magnetic flux through the system. The oscillations are associated with the interference contribution from a special class of electron trajectories confined to the surface of the sample.
Phase-coherent acoustoelectric transport is reported.Aharonov-Bohm oscillations in the acoustoelectric current with visibility exceeding 100% were observed in mesoscopic GaAs rings as a function of an external magnetic field at cryogenic temperatures. A theoretical analysis of the acoustoelectric transport in ballistic devices is proposed to model experimental observations. Our findings highlight a close analogy between acoustoelectric transport and thermoelectric properties in ballistic devices.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
