Hyperfine interaction of electron and nuclear spins in InSb two-dimensional electron gas towards quantum information processing

Nuclear spins in low-dimensional semiconductor structures have attracted growing interest because the long spin coherence time of nuclei facilitates the implementation of quantum information processing (QIP). The quadrupole splitting of ¹¹⁵In have been reported in a single InSb two dimensional electron gas (2DEG) that are of practical importance for the coherent control of the ten nuclear-spin quantum levels and for the implementation of multiple NMR-based quantum bits (≥2). The success of gate controlled InSb quantum wells, allows us to perform pump and probe technique to investigate temperature dependent nuclear spin relaxation time T₁ at different filling factors (ν). Skyrmion like collective spin excitations in the domain walls enhance dynamic nuclear polarization in the quantum Hall ferromagnet around ν = 2 characterized by a short (∼ 60 sec) and temperature-independent T₁. On the other hand, relatively long (∼ 400 sec) and temperature dependent T₁ with following Korringa law have been demonstrated in the absence of the domains as well as collective spin texture at around ν = 3. In addition, the large Zeeman, cyclotron and exchange energy scales of the InSb 2DEG favour to demonstrate the resistively detected NMR (RDNMR) signal at elevated temperature up to 6 K. Our results clearly show that the InSb 2DEG is a suitable candidate for implementation of the high temperature nuclear-spin based quantum information processing