Extended Data Fig. 1: Spin-polarized STM measurements on an as-grown 40-UC FeTe film under opposite magnetic fields.
a, Schematic of spin-polarized STM measurements on FeTe films. Some iron atoms from the surface of FeTe attached to the apex of the PtIr tip make it spin-polarized. Its polarization direction can be controlled by applying an external magnetic field μ0H. b,c, STM images (20 × 20 nm2) of the same region in Fig. 1a on the as-grown 40-UC FeTe film at μ0H = +4 T (b) and μ0H = −4 T (c) (Vs = −15 mV, Is = 5 nA and T = 4.2 K). The STM images in b and c are measured using magnetic Fe-functionalized tips from the surface of FeTe. Under opposite magnetic fields, the spin polarization of the STM tip is reversed, causing the double-stripe pattern to shift by a half-period (aTe). d, Magnetic contrast image, obtained by subtracting b from c, which highlights the bicollinear AFM order of the as-grown 40-UC FeTe film.
