Magnetoconductivity of a spin-polarized two-dimensional electron gas near the (111) silicon surface

Spin susceptibility and polarization field in a dilute two-dimensional electron system in (111) silicon

“…7. Samples had the Hall bar geometry with width of 400 m equal to the distance between the potential probes.…”

“…However, no sign of the enhanced spin susceptibility , which is proportional to the product of the g factor and effective mass m, was observed in parallel-field magnetoresistance measurements. 7 Rather than tending to zero at a finite electron density like in ͑100͒-silicon MOSFETs, 4 the resistance-saturation field B sat , corresponding to the onset of full polarization of the electrons' spins, was found to increase approximately proportion-ally with the electron density. It is worth noting that the valley degeneracy in ͑111͒-silicon MOSFETs is equal to g v =2 ͑as well as the spin degeneracy g s =2͒, rather than g v =6 ͑see, e.g., Ref.…”

“…This has particularly stimulated a new series of experiments in ͑111͒-silicon MOSFETs. [7][8][9][10] It was found in Ref. 10 by an analysis of the temperaturedependent Shubnikov-de Haas oscillations that the strongly increased mass is also the case in a dilute 2D electron system in ͑111͒ silicon with relatively high disorder, as indicated by both the absence of metallic temperature dependence of zerofield resistance and the relatively low mobility.…”

“…The strongest many-body effects have been observed in (100)-silicon metal-oxide-semiconductor field-effect transistors (MOSFETs). This has particularly stimulated a new series of experiments in (111)-silicon MOSFETs [7,8,9,10]. It was found in Ref.…”

Theory of transport properties of the sixfold-degenerate two-dimensional electron gas at the H-Si(111) surface

“…[5][6][7] For instance, at low temperature the magnetoresistance in a parallel magnetic field was measured for a low mobility sample. 3 A MIT at a critical density N MIT Ϸ 3 ϫ 10 11 cm −2 in a g v =2 Si͑111͒ was reported using a metaloxide-semiconductor field-effect transistor ͑MOSFET͒ for a sample with a peak mobility, at low temperatures, of peak Ϸ 2.5ϫ 10 3 cm 2 / Vs. 4 Recently grown samples, [5][6][7] made with hydrogen-passivated Si͑111͒/vacuum ͓H-Si͑111͔͒ structures, had higher mobility Ϸ 2.4ϫ 10 4 cm 2 / Vs with g v =2 at low electron density and with g v = 6 at high electron density. 6 Very recently a still higher mobility Ϸ 10 5 cm 2 / Vs together with a MIT at N MIT Ϸ 0.9 ϫ 10 11 cm −2 and a valley degeneracy g v = 6 was found with H-Si͑111͒ samples.…”