Electromagnetic Drag in Partly Gated 2D Electron System via Highly Confined Screened Plasmons

Generation of photocurrent via photon drag effect enables very fast light detection with response time limited by momentum relaxation. At the same time, photon drag in bulk uniform samples is small by the virtue of small photon momentum. We show that the edge of metal gate placed above a two-dimensional electron system provides highly non-uniform electromagnetic field that enhances the drag effect. We study the drag photovoltage using an exact solution of diffraction problem for two-dimensional electron system with semi-infinite metal gate. We show that the only non-trivial dimensionless parameters governing the drag responsivity are the two-dimensional electron system conductivity scaled by the free-space impedance $$\eta $$ and gate-two-dimensional electron system separation scaled by the incident wavelength $$d{\text{/}}{{\lambda }_{0}}$$ . For radiation with electric field polarized orthogonal to the gate edge, the responsivity is maximized for inductive two-dimensional conductivity with $${\text{Im}}\eta \sim 1$$ and $${\text{Re}}\eta \ll 1$$ , and becomes very small for the capacitive two-dimensional conductivity. The electromagnetic ponderomotive force pushes the charge carriers under the gate at arbitrary two-dimensional conductivity, and the force direction is opposite to that at metal-two-dimensional system lateral contact. These patterns are explained by the dominant role of gated two-dimensional plasmons in the formation of photon drag photovoltage.