RASHBA SPIN SPLITTING IN A GATED HGTE QUANTUM-WELL

Metal-oxide-semiconductor field-effect transistors (MOSFETs) on CdTe/H gTe/CdTe heterostructures are fabricated with silicon dioxide gate ins ulators. In these devices, the density of the quasi two-dimensional el ectron gas in the HgTe quantum well can be tuned in a wide range. in l ow magnetic fields we observe beating patterns in the Shubnikov-de Haa s oscillations that render possible the determination of the coefficie nt alpha of the Rashba term in the Hamiltonian as a function of electr on density. This coefficient consistently describes the splittings obs erved in cyclotron resonance in low magnetic fields.