Phase response of spin-dependent single-hole tunneling in silicon one-dimensional rings

We present the first findings of the transmission phase shift π/2 in the 0.7·(2e²/h) structure of the quantum staircase and in the Kondo-correlated state revealed by an open system which represents a short quantum wire that is inserted within one of the arms of the Aharonov-Bohm (AB) ring inside the p - type self-assembled silicon quantum well prepared on the n - type Si (100) wafer. The quantum well of the p-type is naturally formed between δ-barriers by short-time diffusion of boron. The phase shift in the 0.7·(2e²/h) structure caused by heavy holes is found to be changed from π/2 to π by electrically-detected NMR of the ²⁹Si nuclei thereby verifying the spin polarisation in a quantum wire. The optical nuclear polarisation of the ²⁹Si nuclei induced by circularly polarised light in the n - type Si (100) wafer is shown to effect also on the coherent transport of holes through the quantum wire inserted within one of the AB ring's arms. The quantum conductance revealed by the quantum wire that is embedded in the AB ring inside self-assembled silicon quantum well in the weak localisation regime is studied to demonstrate the coherence of the single-hole transport and negative magnetic resistance effect. The positive/negative transformation of the magnetoresistance in the weakest magnetic fields is found to be caused by the electrically-detected NMR of the ²⁹Si nuclei thereby verifying the effect of the nuclear spin polarisation on a weak antilocalisation.