Phase-dependent electron transport through a quantum wire on a surface

Abstract

Electron transport through a quantum wire in the presence of external periodic energy-level modulations with different on-site phases is studied within the time evolution operator method for a tight-binding Hamiltonian. It is found that in the presence of spatial symmetry of the system and no source-drain and static gate voltages the pumping current can be generated. Moreover, for a wire which is tunnel-coupled to the underlying substrate, the current flowing through an unbiased wire does not fade away but increases with the wire-surface coupling. For randomly chosen phases at every wire site two regimes of the phase-averaged current are found which are related to small and high wire density of states.

Charging time effects and transient current beats in horizontal and vertical quantum dot systems

“…photon-assisted tunnelling, electron pumping or excited states transport [15][16][17][18][19]. The propagation of sinusoidal or train-like pulses through a quantum wire can also lead to charge or spin pumping [20][21][22]. Note that the charge distribution along the wire or the current in both stationary and time-dependent cases also depends on the system geometry e.g.…”

Electronic properties of a quantum wire interacting with a surface: the role of periodically placed impurities

“…Also energy gaps in the spectral function of 1D systems (which are related to the metal-insulator transition) were studied theoretically for freely suspended wires or rings [5,[16][17][18][19] and, e.g., the phase transition or spontaneous spin polarization were observed. Additionally, the conductance across a non-magnetic quantum wire in the presence of electron leakage to the substrate was investigated for various types of surfaces [20,21].…”

Spin-dependent transport through a quantum wire on a graphene surface

“…16 Some reports focus on the transverse transport about a limit QW on a normal surface. 17 The current flowing through an unbiased wire does not fade away but increases with the wire-surface coupling. In one-dimensional systems, two-regime conductance was observed experimentally (metal-insulator transition), which strongly depends on the quality of atomic chains at the surface, e.g., Pb or Au wires on the vicinal Si surfaces.…”

“…Thus, we here apply the spin-dependent transport to a QW coupled with FM leads on a graphene surface. Compared to a vertical QW on the graphene surface 12-15 and a transverse QW on a normal surface, 16,17 our work concentrates on the transport process when it is through the QW on a graphene surface via wire-graphene coupling strength. Further, there are different transport properties whether or not we consider the effects of the graphene surface.…”