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Transient dynamics of spin-polarized injection in helical Luttinger liquids
No full textWe analyze the time evolution of spin-polarized electron wave packets injected into the edge states of a two-dimensional topological insulator. In the presence of electron interactions, the system is described as a helical Luttinger liquid and injected electrons fractionalize. However, because of the presence of metallic detectors, no evidences of fractionalization are encoded in dc measurements, and in this regime the system does not show deviations from its non-interacting behavior. Nevertheless, we show that the helical Luttinger liquid nature emerges in the transient dynamics, where signatures of charge/spin fractionalization can be clearly identified
Interference-induced thermoelectric switching and heat rectification in quantum Hall junctions
No full textInterference represents one of the most striking manifestations of quantum physics in low-dimensional systems. Despite evidence of quantum interference in charge transport having been known for a long time, signatures of interference-induced thermal properties have been reported only recently, paving the way for the phase-coherent manipulation of heat in mesoscopic devices. In this work we show that anomalous thermoelectric properties and efficient heat rectification can be achieved by exploiting the phase-coherent edge states of quantum Hall systems. By considering a tunneling geometry with multiple quantum point contacts, we demonstrate that the interference paths effectively break the electron-hole symmetry, allowing for a thermoelectric charge current flowing either from hot to cold or vice versa, depending on the details of the tunnel junction. Correspondingly, an interference-induced heat current is predicted, and we are able to explain these results in terms of an intuitive physical picture. Moreover, we show that heat rectification can be achieved by coupling two quantum Hall systems with different filling factors, and that this effect can be enhanced by exploiting the interference properties of the tunnel junction
Wigner oscillations in strongly correlated carbon nanotube quantum dots
No full textThe competition between Friedel and Wigner oscillations in the density of strongly interacting carbon nanotubes is inspected within the Luttinger liquid picture. The power laws of the low temperature density oscillations are different from the usual case of quantum dots defined in quantum wires. Temperature plays an important role in the visibility of Wigner oscillations: both Friedel and Wigner oscillations are suppressed, but Friedel oscillations are suppressed at much lower temperature, signalling the incipience of spin-incoherent Luttinger liquid state
Pumping current in interacting helical liquids with two time-dependent magnetic scatterers
No full textCurrent enhancement through a time-dependent constriction in fractional topological insulators
No full textWe analyze the backscattering current induced by a time-dependent constriction as a tool to probe fractional topological insulators. We demonstrate an enhancement of the total current for a fractional topological insulator induced by the dominant tunneling excitation, contrary to the decrease present in the integer case for not too strong interactions. This feature allows us to unambiguously identify fractional quasiparticles. Furthermore, the dominant tunneling processes, which may involve one or two quasiparticles depending on the interactions, can be clearly determined
Generating and controlling spin-polarized currents induced by a quantum spin Hall antidot
No full textSpin-thermoelectric transport induced by interactions and spin-flip processes in two dimensional topological insulators
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