Figure 3: Electronic band structure of the two-dimensional electron liquid (2DEL) emerging from the experimental results, and calculated transport properties.

(a) Sketch of the model band structure purposely built to reproduce the experimental results. Grey areas indicate valence and conduction states; the coloured lines below the conduction states represent a tail of localized states. (b) Actual density of states (DOS) of the model band structure considered for the calculations. The shaded grey area is the DOS relative to the conduction band bottom (CBB) of t_2g d_xy orbital character. Below the CBB lies a tail of 12 localized states, placed at regular intervals of 3 meV from each other, indicated by different colours and type of lines. From the bottom: red solid, dotted, dashed, dot-dashed and then the same sequence repeated in green and blue. Zero energy is fixed at the CBB. (c) Integrated DOS per unit area. The DOS is normalized to obtain for the total charge density hosted by the 12 localized states, n_2D=6 × 10¹¹ cm⁻², that is, the Hall-measured charge depleted by field-effect in the interval V_g=−14 V, −7 V, where the huge Seebeck oscillations are visible. (d) Phonon-drag calculated for the model DOS. The dotted vertical lines indicate the bottom energy of each localized state, the solid line is the CBB. S_g oscillates at each intersection of E_F with the bottom energies. (e) Diffusive Seebeck: like S_g it oscillates in correspondence with the depletion of each localized state, but in absolute value is about three orders of magnitude smaller than S_g. (f) Electric resistivity ρ in 3D. To obtain the sheet resistance, ρ must be rescaled by the 2DEL thickness t, that is, ρ=R_sheet·t.