Figure 3

(a) Schematic illustration of symmetric-antisymmetric gap (Δ_SAS) formation and the corresponding wave functions. AS(S) denotes the antisymmetric (symmetric) state, and U(L) denotes upper (lower) layer state. (b) Schematic drawing of the LL evolution for the broken-symmetry states with B field. The solid (dashed) line indicates the layer asymmetric (symmetric) levels. The valley (K, K’) and spin (↑, ↓) degrees of freedom are colour coded. The experimentally observed transitions are marked by circles. (c) The longitudinal resistance R_xx and (d) the Hall conductivity σ_xy as a function of total filling factor ν_tot at B fields from 4.5 T to 14 T with a step of 0.5 T for D1. The arrows indicate the R_xx dip and the corresponding Hall plateaus for the broken-symmetry QH state in zeroth and first landau levels. (e) Colour rendition of R_xx as a function of the total filling factor ν_tot for D1. Field-dependent R_xx (f) at ν_tot = −2 and 0 for D1 and (g) at ν_tot = 2 for D2 at 1.8 K. The R_xx dip and hump are marked by the arrows. (h) Temperature evolution of the longitudinal resistance, ΔR_xx (R_xx(T) – R_xx (20 K)), from 1.8 K to 20 K as function of ν_tot at different magnetic fields for D2. The scale bar is 1 kΩ. The green dot lines between (g) and (h) indicate the corresponding magnetic fields from 4 T to 9 T in 1 T steps for data shown in (h).