Files a.txt and b.txt contain the raw data for the corresponding panels in Figure S5 in  the Supplementary information. 
 File a.txt contain three columns (k_y, um^-1	Energy (eV) V_detection 	Energy (eV) H_detection) and the values of the third and the second should be plotted versus values in the first one. 
File b.txt contain two columns  titled "k_y, um^-1	TE-TM splitting (ueV)" and the values of the second one  should be plotted versus values in the first one. 
