Rashba spin splitting in a gated HgTe quantum well

Abstract

Metal-oxide-semiconductor field-effect transistors (MOSFETs) on CdTe/HgTe/CdTe heterostructures are fabricated with silicon dioxide gate insulators. In these devices, the density of the quasi two-dimensional electron gas in the HgTe quantum well can be tuned in a wide range. In low magnetic fields we observe beating patterns in the Shubnikov-de Haas oscillations that render possible the determination of the coefficient α of the Rashba term in the Hamiltonian as a function of electron density. This coefficient consistently describes the splittings observed in cyclotron resonance in low magnetic fields.

Spin properties of free electrons and holes in Hg1-xCdxTe/CdTe quantum well

“…Thus, spin precession due to Dresselhaus contribution, if any, should be negligible too. On the other hand, the spin-splitting in asymmetric n-type HgTe single quantum wells, due to Rashba mechanism in combination with the inverted band structure, was found to be very large [12,[25][26][27]. By this reason we shall neglect the Dresselhaus contribution altogether.…”

“…Spatial quantization of the wave function in the well gives rise to 2D electron and hole energy subbands, where interplay between the inverted and normal bands arises. If Hg 1−x Cd x Te bands are inverted, two distinct heterostructure regimes can be realized [12][13][14][15][16][17]. When Hg 1−x Cd x Te quantum well is thin enough then the first electronic subband E1 is pushed up high enough, above the first heavy-hole energy subband H1.…”

“…For Hg 0.3 Cd 0.7 Te / HgTe QW the critical thickness is 6.3 nm [10]. Below we shall be interested in inverted 2D semiconductors represented by Hg 1−x Cd x Te / CdTe, where the giant Rashba SO splitting in electronic 2D structures have recently aroused much interest due to their possible application in spintronics [11][12][13][14][15][16][17]. The Rashba spin-splitting of up to 30 meV has been measured, which is almost an order of magnitude larger than in A 3 B 5 compounds [2].…”

Spin properties of Hg1–xCdx Te/CdTe quantum wells

“…This means that their spin precession trajectories are elliptical rather than circular. The confinement of free electrons and holes between the barriers, for example in HgTe/CdTe quantum well, will result in spatial energy quantization, which due to strong interaction between inverted energy subbands gives rise to new interesting properties [6][7][8]. Furthermore, in the inverted QWs the Rashba spin-splitting of up to 30 meV has been measured, which is almost an order of magnitude larger than in A 3 B 5 compounds.…”

Nonlinear terahertz response of HgTe/CdTe quantum wells

“…[5][6][7][8] One fascinating property leading to these interests is the inverted band structure, which is due to the enhancement of spin orbit coupling when the well thickness increases up to a critical value (approximately 6.4 nm). 9,10 The band inversion lifts the first heavy-hole sub-band, H1, up above the first electron sub-band, E1, resulting in a quasizero gap, which is reopened with increasing thickness of the "well" layer. 11 HgTe/CdTe QWs have been found to exhibit large Rashba spin-obit splitting, 12 quantum Andreev effect, 13 weak anti-localization effect, 10 and so on.…”