Effects of Thickness on the Spin Susceptibility of the Two Dimensional Electron Gas

Using available quantum Monte Carlo predictions for a strictly 2D electron gas, we estimate the spin susceptibility of electrons in actual devices taking into account the effect of the finite transverse thickness and finding very good agreement with experiments. A weak disorder, as found in very clean devices and/or at densities not too low, just brings about a minor enhancement of the susceptibility.

Figure 1

Spin susceptibility in the 2DEG. The thick full curve is the QMC prediction for a strictly 2D system [13]. Experimental results are given by the thick dashed curve for a GaAs HIGFET [9] and by various symbols, corresponding to different samples, for AlAs QW’s [10]. The thin dashed and full curves add the thickness effect onto the QMC prediction [13] for GaAs and AlAs, respectively. Finally, the thick and thin dot-dashed curves provide the QMC prediction without and with inclusion of thickness for AlAs, as obtained from the polarization field $B_P$ [see Eq. (5) in the text]. The arrow indicates the location of the MIT transition in AlAs.

Figure 2

Difference of QMC energies of unpolarized and polarized phases for the strictly 2DEG (solid line, Ry) and with the thickness of the GaAs HIGFET (dashed line, ${\mathrm{Ry}}^{*}$).

Figure 3

Effect of a weak disorder appropriate to the GaAs HIGFET on the spin susceptibility. Upper and lower dotted curves are for the strictly 2DEG and for a 2DEG with the GaAs HIGFET thickness. Other curves as in Fig. 1.