We observe microwave induced nonlocal resistance in magnetotransport in single and bilayer electronic systems. The obtained results provide evidence for an edge state current stabilized by microwave irradiation due to nonlinear resonances. Our observation are closely related to microwave induced oscillations and zero resistance states in a two-dimensional (2D) electron system.A few years ago, a new class of the non-equilibrium phenomena was observed, when an ultrahigh mobility 2D electron gas, subjected to a weak magnetic field was also irradiated with microwaves [1]. This included microwaveinduced resistance oscillations (MIROs) [2] and a zeroresistance state (ZRS) [3]. Many microscopic mechanisms of MIRO have been proposed, mainly originating from the scattering-assisted electron transitions between different Landau levels in the presence of microwave excitation. The most developed theories account for spatial displacement of electrons along the applied dc field under scattering-assisted microwave absorption ("displacement" mechanism) [4,5], and an oscillatory contribution to the isotropic part of the electron distribution function ("inelastic" mechanism) [6]. Both these mechanisms describe the periodicity and phase of MIROs observed in experiments and can lead to an absolute negative conductivity σ < 0. ZRS emerges from the instability of a homogeneous state with σ < 0 and the nonequilibrium phase transition into a domain state with zero net resistance [22]. Two more alternative approaches to the MW-induced effects in dissipative resistance, such as the radiation-driven electron-orbit [8] and near-contact region [9] models, have been recently proposed.A striking similarity has been emphasized between QHE and ZRS: both effects exhibit vanishing longitudinal resistance R xx , when the propagation along the sample edge is ballistic, although the magnetic field intensity is quite different. One naturally expects that a strong magnetic field stabilizes edge states, and, therefore, that the QHE is robust against disorder [10]. It has been shown that microwave radiation can also stabilize guiding along sample edges in the presence of a relatively weak magnetic field leading to a ballistic dissipation-less transport regime, which also results in vanishing R xx [11]. Indeed such transport is much less robust than those in the QHE regime and requires samples with ultrahigh electron mobility. This model also avoids the fundamental assumption made in those approaches [4][5][6] that cyclotron harmonic absorption at high j can be explained by the presence of the short range potential, while in high mobility samples the long range potential plays a dominant role.The method used for probing the property of the edge states is nonlocal electrical measurement. If a finite voltage is applied between a pair of the probes, a net current appears along the sample edge, which can be detected by another pair of voltage probes far away from the bulk current path.In this letter we present studies of the nonlocal resistance in narrow (NQ...

We observe the phonon-drag voltage oscillations correlating with the resistance oscillations under microwave irradiation in a two-dimensional electron gas in perpendicular magnetic field. This phenomenon is explained by the influence of dissipative resistivity modified by microwaves on the phonon-drag voltage perpendicular to the phonon flux. When the lowest-order resistance minima evolve into zero-resistance states, the phonon-drag voltage demonstrates sharp features suggesting that current domains associated with these states can exist in the absence of external dc driving.

Recent advances in guiding and localizing light at the nanoscale exposed the enormous potential of ultrascaled plasmonic devices. In this context, the decay of surface plasmons to hot carriers triggers a variety of applications in boosting the efficiency of energy-harvesting, photocatalysis, and photodetection. However, a detailed understanding of plasmonic hot carrier generation and, particularly, the transfer at metal–semiconductor interfaces is still elusive. In this paper, we introduce a monolithic metal–semiconductor (Al–Ge) heterostructure device, providing a platform to examine surface plasmon decay and hot electron transfer at an atomically sharp Schottky nanojunction. The gated metal–semiconductor heterojunction device features electrostatic control of the Schottky barrier height at the Al–Ge interface, enabling hot electron filtering. The ability of momentum matching and to control the energy distribution of plasmon-driven hot electron injection is demonstrated by controlling the interband electron transfer in Ge, leading to negative differential resistance.

We report results on the control of barrier transparency in InAs/InP nanowire quantum dots via the electrostatic control of the device electron states. Recent works demonstrated that barrier transparency in this class of devices displays a general trend just depending on the total orbital energy of the trapped electrons. We show that a qualitatively different regime is observed at relatively low filling numbers, where tunneling rates are rather controlled by the axial configuration of the electron orbital. Transmission rates versus filling are further modified by acting on the radial configuration of the orbitals by means of electrostatic gating, and the barrier transparency for the various orbitals is found to evolve as expected from numerical simulations. The possibility to exploit this mechanism to achieve a controlled continuous tuning of the tunneling rate of an individual Coulomb blockade resonance is discussed.