Magnetoresistance and microwave photoresistance of a periodically modulated high-mobility 2D electron gas

We have measured the magnetoresistance ($R_{xx})$ and the microwave (MW) photoresistance on a high-mobility 2D electron gas patterned with a large period (1200 and 1500 nm) triangular antidot lattice [1]. Our experiments were performed in a MW frequency range from 26 to 150 GHz and at temperatures (T) from 0.3 to 10 K, samples were Hall bars having low T mobility as high as 2.5 x 10$^{6}$ cm$^{2}$/Vs after the patterning. We observed remarkably sharp (up to seventh order) geometrical resonance (GR) peaks in $R_{xx}$. Moreover, under irradiation, MW-induced resistance oscillations (MIRO) and magnetoplasmon resonance (PR) modes were observed. Analysis shows that MIRO, MP, and GR are decoupled from each other in these large-period modulated 2D electron gas samples. [1] Yuan \textit{et al}, Phys. Rev. B \textbf{74}, 075313(2006).