Interplay of chiral and helical states in a quantum spin hall insulator lateral junction by Calvo, M, de Juan, F, Ilan, R, Fox, E, Bestwick, A, Mühlbauer, M, Wang, J, Ames, C, Leubner, P, Brüne, C, Zhang, S, Buhmann, H, Molenkamp, L, Goldhaber-Gordon, D