Fig. 4: Oscillating exciton binding energy (B = 12 T).
a, Rxx of the W layer as a function of Vb and T at charge neutrality. b, Exciton binding energy as a function of Vb (bottom axis for device 1 and top axis for device 2). It oscillates on a monotonically decreasing background. The horizontal dashed line marks the cyclotron energy Ec (comparable for electrons and holes). c,d, Rxx (left axis; c), σxx (right axis; c) and σxy (d) versus Vb at varying temperatures (1.5 K to 14.5 K in 1-K step) for device 1. The dashed lines in d denote the quantized values. As Vb increases, the EI state (with increasing Rxx and decreasing σxx and σxy) transitions into the QH states (with decreasing Rxx and σxx and quantized σxy) at low temperatures. The fully filled LLs (νe and νh) are labelled in a and denoted by the vertical purple lines in b–d.
