Waveform control of currents in graphene by chirped few-cycle lasers

Abstract

The residual current density in monolayer graphene driven by an intense few-cycle chirped laser pulse is investigated via numerical solution of the time-dependent Schrödinger equation in the light-fielddriven regime. Strikingly, it is found that a purely chirped laser pulse breaks the inversion symmetry in graphene, generating a residual directional current, which is absent for a Fourier-transform limited pulse (2017 Nature 550 224) and is attributed to the chirp-dependent Landau-Zener-Stückelberg interference among different quantum pathways in the reciprocal space. Moreover, the directionality of such a current changes with laser chirp rate following a sine-functional way, which possibly provides a novel application in ultrafast photo-electronics based on two-dimensional materials.

Quantum Control via Landau-Zener-Stückelberg-Majorana Transitions

“…The theory of nonadiabatic transitions in the vicinity of a conical intersection and related interference were addressed in several works for graphene (Rozhkov et al, 2016) and other related materials (Heide et al, 2021;Montambaux, 2018;Wu et al, 2020). Here, we note that the Dirac cones and Dirac points are important to many objects, including massless electrons in graphene and in conducting edge states in topological insulators.…”

Atomic real-space perspective of light-field-driven currents in graphene

“…Due to the weak screening effect and the high laser damage threshold, strong light fields can be applied to the single atomic layer of carbon atoms [9][10][11][12][13]. The interaction with strong light fields is well elucidated by considering only two electronic structures, namely π and π * bands, allowing to give clear physical interpretations on the origins of the strong-field-driven high-order harmonics and residual electric currents [9][10][11][12][13][15][16][17][18], and profound insights and predictions [14,15,[18][19][20][21][22][23][24], for example, the emergence of the valley polarization induced by two counter-rotating circularly polarized fields [22] and the Berry phase interferometry in reciprocal space [19].…”