Fig. 4: Quenching the 1e quantum ring by detuning.
From: Electrical control of spins and giant g-factors in ring-like coupled quantum dots
a Measurement of dI/dVds versus Vds recorded along the red detuning vector (c.f. Fig. 1f) for B|| = 0.1 T. Detuning is defined as ΔVL,R = (VR − VR0) − (VL − VL0), where (VR0,VL0) are the side-gate voltages when the left and right QD levels are degenerate. EZ denotes the Zeeman splitting. b Numerical calculation of the states for B|| = 0.1 T. Here detuning (Δorb) refers to the extrapolated energy difference between the unperturbed orbitals in the left and right QD (see schematic in h). The colour represents the calculated orbital angular momentum (blue: Lz, = −1.3 ħ, black: Lz, = 0, red: Lz, = 1.3 ħ). c Experimental values of |g*| for B|| = 0.04 T (blue) and B|| = 0.1 T (orange), extracted from the GS-ES1 transition using on a linear approximation. In the case of B|| = 0.04 T, |g*| at zero detuning corresponds to |g1*|, while we find a strongly reduced value at B|| = 0.1 T due to the orbital change of the 1st excited state. d Same as panel a, but for B|| = 0.2 T and a larger detuning range, showing a detuning-induced spin-change of the 1e ground state. e, f Measurement of dI/dVds and numerical calculation as a function of detuning for B⊥ = 0.1 T, where SOI from the ring supresses Zeeman splitting. g Experimental values of g* for the GS-ES1 transition at B⊥ = 0.1 T. h Calculated probability density (|Φ|2) of the lowest energy state at infinitesimal B||-field for three different detuning energies. The error bars in c and g represent the uncertainty in energy gap extraction due to measurement noise and resolution.
