Fig. 2: Point-defects: Scanning tunneling microscopy (STM) topographies and two-dimensional fast Fourier transforms (2D-FFTs).
From: Hydrogenic spin-valley states of the bromine donor in 2H-MoTe2
a, b STM topographies of MoTe (Isetpoint = 180 pA) and BrTe (Isetpoint = 400 pA), respectively, measured at sample bias −1 V and temperature of 77 K. The color bar quantifies the topographic height. A non-linear color scale has been used to improve the visibility of Te atoms in the background. The white scale bar on each panel is 3 nm long. c, d Maps of the amplitude of the 2D-FFTs applied to the topographic images. The color bar quantifies the FFT amplitude. A non-linear color scale has been employed to improve the visibility of the FFT peaks of small amplitude. The black scale bar on each panel is equal to the length of the reciprocal lattice vector \(\parallel {\overrightarrow{a}}^{\star }\parallel =20.44\) nm−1. c, e For MoTe, only the Bragg peaks (pink plus symbol) are observed. e–g For BrTe, peaks in the Fourier amplitude are observed at the intra-valley Fourier components mi = qj − qi (green star symbols) and peaks of strongest amplitude are observed at the inter-valley Fourier components \({{{{{{{{\bf{q}}}}}}}}}_{i}={{{{{{{{\bf{q}}}}}}}}}_{j}-{\bar{{{{{{{{\bf{q}}}}}}}}}}_{i}\) (red and blue disc symbols) and \({{{{{{{{\bf{h}}}}}}}}}_{i}={{{{{{{{\bf{q}}}}}}}}}_{i}-{\bar{{{{{{{{\bf{q}}}}}}}}}}_{i}\) (orange disc symbols). The arrows show how the Fourier components arise from the valleys wavevectors qj and \({\bar{{{{{{{{\bf{q}}}}}}}}}}_{i}\).
