Even-Denominator Fractional Quantum Hall State in Conventional Triple-Gated Quantum Point Contact

Fractional quantum Hall states with even denominators have attracted attention owing to their novel carrier interactions and possible applications to error-free quantum manipulations. A well-known example is the nu = 5/2 state where a non-Abelian topological order is expected. Although the 3/2 state has not been reported in wide 2D systems for GaAs, the formation of this state has been experimentally confirmed at the microscopic scale, suggesting a possible manipulation of non-Abelian characteristics in microscopic areas. These observations were made using ultra-high-quality GaAs 2D systems with mobility >1x107 cm2/Vs. We present the observation of the nu = 3/2 state using conventional quantum point contact (QPC) fabricated on a high-mobility (not ultra-high-mobility) wafer. The centre gate placed on the QPC constriction is essential for realising the nu = 3/2 state. The even-denominator state in the conventional QPC presents new possibilities for quantum information processing based on semiconductor quantum nanostructures.