Figure 2.

FFT analysis of the stripe modulations in strained FeSn/SrTiO₃(111) films. a, STM topographic image of stripe modulations of Sn honeycomb lattice, set point: V = 100 mV, I = 5.0 nA. b, FFT of the image in (a). Bragg peaks along three directions q₁, q₂, and q₃ are denoted by Q₁, Q₂, and Q₃ in blue, green and red circles, respectively. The diffraction peak of the stripe modulation is denoted by Q₄ in cyan circles. There is an angle of 13.8° between Q₄ and Q₁ directions. c, Reverse-FFT of the peak Q₄ in (b). The distribution of the stripes coincides with the topography in (a). d, Line profiles along the Q₁, Q₂, Q₃ and Q₄ directions in (b). As a reference, the line profile across the Bragg lattice Q is obtained from the FFT of a perfect honeycomb lattice. e, Close-up view of the Bragg peaks Q₁, Q₂, Q₃, and Q. The peak position is marked by arrows in corresponding colors. f, Perfect honeycomb with lattice vector a marked. g, Deformed honeycomb with lattice vectors a₁ and a₂ marked.