Optical Probes and Electron Correlations in Far-From-Equilibrium Graphene
Abstract
Research Problem: Understanding and controlling the nonequilibrium dynamics and ordering of many-body systems remain among the least understood problems in condensed matter physics. Recent pioneering theoretical and experimental studies of light-induced phenomena have led to the recognition that interacting electrons coherently driven far from equilibrium can exhibit novel ordered states with remarkable properties that are otherwise difficult to achieve. Technical Approaches: We propose a concerted effort to predict, discover, and investigate nonequilibrium phenomena in photoexcited and photodriven graphene Ð a prototypical two- dimensional material with unique band structure and striking properties. Low dimensionality will allow us to create highly controllable settings for inducing the strongest possible light- matter coupling. Using intense terahertz and midinfrared pulses to drive the nonequilibrium dynamics in monolayer graphene, we will investigate 1) extreme nonlinear optical dynamics of Dirac fermions in graphene in free space and in a cavity, 2) ultrafast population inversion, gain, and lasing of nonequilibrium photogenerated carriers in graphene, and 3) a photodriven transition from a quantum Hall antiferromagnet to a Floquet-Chern insulator in graphene. This set of nonequilibrium phenomena have been specifically chosen to capture a range of increasing importance of electron-electron correlations. Anticipated Outcomes: The ultimate goal of this project is to establish a set of criteria for predicting electromagnetically induced exotic phases in materials by using graphene as an ideal model system. We anticipate creating and gaining insight into fundamentally new states of matter that simply cannot be realized in equilibrium. We want to understand the roles of band structure, electronic correlations, quantum coherence and reduced dimension- ality in the nonlinear and ultrafast response of Dirac fermions in graphene. We will provide evidence for coherent band structure modifications; generate terahertz waves via resonant four-wave mixing employing giant ?(3); induce collective nonperturbative coupling of 2D Dirac fermions with high-quality-factor terahertz cavity photons; determine the basic pa- rameters for ultrafast carrier thermalization, cooling, scattering, and recombination; explore the spectral, temperature, and density regimes where population inversion is possible; under- stand the effect of a magnetic field on the population dynamics, gain, and lasing; elucidate dynamical phases of correlated 2D electrons in the simultaneous presence of a strong DC magnetic field and a strong AC electric field; and understand the constraints imposed by topology on the collective 2D electronic state driven by circularly polarized light. Impact on DoD Capabilities: Solid-state research is closely connected to military appli- cations and reflects the synergy between device development and basic physics. Electronic and photonic devices are used in essentially all military-related technologies: surveillance and target acquisition; command, control, and communications; electronic warfare; and re- connaissance. Our research aims to understand the science vital for creating next-generation devices, which are anticipated to exploit materials physics that does not exist in equilibrium.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 16, 2018
- Source ID
- W911NF1710259
Entities
People
- Junichiro Kono
Organizations
- Army Contracting Command
- Rice University
- United States Army