Laser induced modulation of the Landau level structure in single-layer graphene

TL;DR

This paper analytically studies how intense circularly polarized terahertz radiation modifies the Landau level structure, pseudospin polarization, and quantum revivals in single-layer graphene, revealing complex dynamical effects and potential experimental detection methods.

Contribution

It provides the first perturbative analytical analysis of the radiation-induced modifications to Landau levels and pseudospin dynamics in graphene under intense terahertz radiation.

Findings

Discovery of non-trivial, level-dependent photoinduced gaps in Landau levels.

Identification of shifts in revival times and modulation of pseudospin oscillations.

Prediction of additional quantum revivals and beating patterns in wave function dynamics.

Abstract

We present perturbative analytical results of the Landau level quasienergy spectrum, autocorrelation function and out of plane pseudospin polarization for a single graphene sheet subject to intense circularly polarized terahertz radiation. For the quasienergy spectrum, we find a striking non trivial level-dependent dynamically induced gap structure. This photoinduced modulation of the energy band structure gives rise to shifts of the revival times in the autocorrelation function and it also leads to modulation of the oscillations in the dynamical evolution of the out of plane pseudospin polarization, which measures the angular momentum transfer between light and graphene electrons. For a coherent state, chosen as an initial pseudospin configuration, the dynamics induces additional quantum revivals of the wave function that manifest as shifts of the maxima and minima of the autocorrelation function, with additional partial revivals and beating patterns. These additional maxima and beating patterns stem from the effective dynamical coupling of the static eigenstates. We discuss the possible experimental detection schemes of our theoretical results and their relevance in new practical implementation of radiation fields in graphene physics.