Fig. 3: Pseudo-magnetic field-induced ultra-slow carrier dynamics.
From: Pseudo-magnetic field-induced slow carrier dynamics in periodically strained graphene
a Schematic illustration of our femtosecond pump–probe measurement setup. Pump pulses (blue) excite charge carriers and probe pulses (green) are used to monitor the sample responses at different delay times (Δt) after the pump pulses arrive at the sample. Left inset: magnified image of a single nanopillar structure. b Schematic illustration of relaxation process of photoexcited carriers in pristine graphene with massless Dirac cones (left) and strained graphene attaining pseudo-Landau levels (right). The formation of pseudo-Landau levels can significantly decelerate the relaxation process, resulting in a longer decay time in strained graphene (\({\tau }_{1}\) « \({\tau }_{2}\)). c Measured reflection change as a function of the delay time on control (black) and nanopillar (red) samples. Symbols are measurement data; lines are fitting data for the decay region. The decay times of both samples are extracted from fitting data; \({\tau }_{1}\) = 0.13 ps (Control) and \({\tau }_{2}\) = 1.66 ps (Nanopillar). Inset: Normalized reflection change of both samples from −0.15 to 1 ps. d, e Normalized reflection change of control (d) and nanopillar (e) samples measured at 300 K (black) and 4 K (red). Symbols are measurement data; lines are fitting data for the decay region.
