(a) The SHE contribution existed in H-pattern measurement as explained in the text. L stands for the center to center distance of two adjacent bars. w is the horizontal bridge width. Note that the R_sH is positive. (b) Scanning electron microscopy image of H-pattern device, with several vertical bars separated by various distance L and connected by central bridge of width w = 40 nm. The R_nl is obtained from bar distance L of 200 nm unless specifically mentioned.