Fig. 5: Emergent correlated state at ν ≈ 2.
From: Visualizing delocalized correlated electronic states in twisted double bilayer graphene
a Gate-dependent dI/dV spectra in ABBC region for 11.5 V < VG < 33.5 V (1 < ν < 3). Spectroscopy parameters: modulation voltage VRMS = 1 mV; initial VBias = –100 mV, I0 = 0.5 nA. b Magnitude of CFB energy-splitting extracted as a function of gate voltage (filling factor) for three stacking regions. The error bars were estimated by combining fitting uncertainty, finite temperature broadening, and an instrumental broadening of ~1 mV. c Spatially resolved dI/dV spectra measured at VG = 22.5 V (ν = 2) along the white dashed line in the topographic image (which goes through all three tDBLG stacking regions). Scanning parameters: VBias = –100 mV, I0 = 0.1 nA. Spectroscopy parameters: modulation voltage VRMS = 1 mV; initial VBias = –100 mV, I0 = 0.5 nA. d Hartree-Fock band structure of tDBLG and e the corresponding isospin-resolved DOS for an isospin-polarized solution at ν = 2 (E = 0.12 V/nm, εeff = 14, dS = 50 nm). For clarity only bands from a single valley are shown. f Energy offset (i.e., splitting) between the isospin sub-bands averaged over the mini-Brillouin zone as a function of filling factor for 1.5 < ν < 2.5. g Calculated Hartree-Fock LDOS for ν = 2 at different positions across the moiré unit cell corresponding to white dashed line in c. CFB conduction flat band, VFB valence flat band.
