Year: 2025
Type: article
Abstract: We employ ultrabroadband terahertz (THz) spectroscopy to expose the high-frequency transport properties of Dirac fermions in monolayer graphene. By controlling the carrier concentration via tunable electrical gating, both equilibrium and transient optical conductivities are obtained for a range of Fermi levels. The frequency-dependent equilibrium response is determined through a combination of time-domain THz and Fourier-transform infrared spectroscopy for energies up to the near-infrared, which also provides a measure of the gate-voltage dependent Fermi level. Transient changes in the real and imaginary parts of the graphene conductivity are electro-optically resolved for frequencies up to 15 THz after near-infrared femtosecond excitation, both at the charge-neutral point and for higher electrostatic-doping levels. Modeling of the THz response provides insight into changes of the carrier spectral weights and scattering rates, and reveals an additional broad-frequency (≈ 8 THz) component to the photo-induced response, which we attribute to the zero-momentum mode of quantum-critical transport observed here in large-area CVD graphene.
Source: Scientific Reports
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,690
Awards: G1229526393, G1243123360, G1286236842, G1286251239, G2371548206, G2618837358, G303061748, G30714459, G3083819904, G3685081974, G419881185, G42916606, G4501827968, G4711507462, G495301720, G498139845, G5261056217, G5570207115, G650090426, G6550344761, G6652958823, G7283024673, G8382000481, G911061179, G969889393
OpenAlex ID: W4409669138