Fig. 4: Local photothermoelectric driving force and resulting nanoscale charge flow.
a, Measured resistivity of a metasurface device as a function of gate voltage. Insets: chemical potentials of the gold-pinned and bare graphene regions for three gate voltages as indicated in b. b, Measured gate-dependent current (dashed line) compared with calculated ΔS0 (solid fill). Inset: illustration of the gated device configuration, with tip-localized heating and corresponding net carrier motion. c, Spatial distribution of S0. d, Snapshot of the calculated Te distribution at the time of the incident pulse peak (0 fs). e, Photothermoelectric x acceleration field (along the principal nanoantenna axis) at Vg = 0 V and 0 fs. f, Hydrodynamic velocity field for the hole fluid at Vg = 0 V and 0 fs.
