Figure 1

(a) Energy-band diagram of the MOS system showing the overlap of the 2DEG and donor electron wave functions. (b) Schematic of the aFET used, where the drain (D) and source (S) are separated by three gates (DG, CG, and SG). ${}^{31}\mathrm{P}$ donors are present under all three gates while ${}^{75}\mathrm{As}$ donors reside under the CG region only. (c–e) Three possible EDMR mechanisms affecting the 2DEG current $I$ (dark blue arrow), and the expected change in resistivity $\Delta \rho$ associated with each mechanism: (c) bolometric heating, (d) spin-dependent scattering, and (e) polarization transfer. The light grey arrows represent energy transfer between the systems, while the dashed line in (d) represents elastic scattering. See text for the definition of symbols.Reuse & Permissions

Figure 2

(a) EDMR spectra obtained in $X$ and (b) $W$ band. The 2DEG, phosphorus (P) and arsenic (As) resonances are indicated along the traces. Sections of the EDMR spectra are magnified by $10\times$ and offset for clarity. The gate bias was 0.3 V and the drain bias was 40 mV in both measurements.Reuse & Permissions

Figure 3

Temperature dependence of device resistivity for gate voltages $V_g=0.20–0.45\mathrm{V}$. Solid lines correspond to linear fits to the data for $T\le 8\mathrm{K}$.Reuse & Permissions

Figure 4

Microwave power dependence of the 2DEG (green circles) and ${}^{31}\mathrm{P}$ (blue triangles) EDMR signal intensities measured in $X$ (closed symbols) and $W$ band (open symbols). The lines represent best fits to $\Delta \rho /{\rho }_0$ as described in the main text. ${}^{75}\mathrm{As}$ signals have similar power dependences and are not shown. The gate bias was 0.3 V in all measurements.Reuse & Permissions