Photon-assisted transport in semiconductor nanostructures

Abstract

In this review we focus on electronic transport through semiconductor nanostructures which are driven by ac fields. Along the review we describe the available experimental information on different nanostructures, like resonant tunneling diodes, superlattices or quantum dots, together with the theoretical tools needed to describe the observed features. These theoretical tools such as, for instance, the Floquet formalism, the non-equilibrium Green's function technique or the density matrix technique, are suitable for tackling with photon-assisted transport problems where the interplay of different aspects like nonequilibrium, nonlinearity, quantum confinement or electron-electron interactions gives rise to many intriguing new phenomena. Along the review we give many examples which demonstrate the possibility of using appropriate ac fields to control/manipulate coherent quantum states in semiconductor nanostructures.

Quantum router based on ac control of qubit chains

“…Thus, Bob will receive a state with c B = |c B |e iθ . In order to restore the full state (18), one has to know the total phase shift θ, which requires full knowledge of the transfer process, i.e., one has to calibrate the chain before use. Subsequently, a fixed unique phase shift has to be applied to every signal coming from the hub.…”

“…Such driving renormalizes the tunnel matrix elements and has been investigated previously in the context of ac-driven mesoscopic transport [18,21,23]. In a recent theoretical work [24], it has been suggested to temporarily suppress tunneling between specific neighboring sites of an optical lattice, such that a particle will be transported into a direction of choice.…”

Resonant second-harmonic generation in a ballistic graphene transistor with an ac-driven gate

“…In theoretical investigations for low doping (Fermi energy E F close to the Dirac point) and high frequencies , with E F and of comparable magnitude (we put = 1), a true quantum mechanical description becomes necessary. For time-dependent transport in two-dimensional electron gases (2DEGs) in semiconducting heterostructures, displaying a quadratic dispersion relation, photon-assisted tunneling in time-harmonic potentials is described well within a Floquet theory framework and have been investigated for a long time [26][27][28][29]. Here, we study theoretically a ballistic field effect transistor with a harmonic drive applied to the top gate, see Fig.…”

Transport, shot noise, and topology in AC-driven dimer arrays

“…The second moment follows from equation (13) together with the solution of the first two equations. Subtracting the time-derivative of á ñ N 2 , we obtain the zero-frequency noise…”

“…Then for not too small frequencies, the driving essentially renormalizes the inter-dot tunnel coupling [9][10][11][12] and, thus, allows the emulation of a dimer chain with highly tunable tunneling. In the corresponding transport setting, i.e., in the presence of electron source and drain, one expects a corresponding current suppression [13,14] which has been measured in double quantum dots [15,16]. Moreover, the driving may have significant impact on the shot noise [17].…”