Polarization-induced ultrahigh Rashba spin-orbit interaction in ZnO/CdO quantum well

Spin polarization in quantum point contact based on wurtzite topological quantum well

“…48 The eight-band k.p Hamiltonian of the wurtzite semiconductor is solved in the QW under a spontaneous and piezoelectric polarization field, which breaks the inversion symmetry with large Rashba SOC (nondiagonal terms in eqn (1)) as well as an inverted band structure. 24,25 Fig. 1(b) clearly shows an inverted band dispersion where the first electron sub-band E 1 already enters the first light sub-band L 1 .…”

“…19 Very recently, wurtzite semiconductor quantum wells (QWs) have been found to host a 2D TI. [23][24][25] Distinct from the zinc blende HgTe/CdTe and InAs/GaSb QWs, 26,27 the topological states in wurtzite QWs are triggered by a strong polarization field rather than a bulk-inverted band structure or broken gap band alignment. As a result, a large Rashba SOC is induced near to the band inversion due to a strong coupling between the electron and light hole.…”

“…As a result, a large Rashba SOC is induced near to the band inversion due to a strong coupling between the electron and light hole. 25 The Rashba SOC can reach as high as 83 meV nm, almost two orders of magnitude higher than those of the GaN- and ZnO-based two-dimensional electron systems (2DESs) with trivial band structures. 28,29 The combined edge channels with a large SOC make wurtzite topological QWs attractive to study diverse spin-related features, including spin texture, 30 spin–orbit torque, 31 and spin polarization.…”