We study ultra-high-mobility two-dimensional(2D)electron/hole systems with high precision capacitance measurement.It is found that the capacitance charge appears only at the fringe of the gate at high magnetic field w...We study ultra-high-mobility two-dimensional(2D)electron/hole systems with high precision capacitance measurement.It is found that the capacitance charge appears only at the fringe of the gate at high magnetic field when the 2D conductivity decreases significantly.At integer quantum Hall effects,the capacitance vanishes and forms a plateau at high temperatures T≥300 m K,which surprisingly disappears at T≤100 m K.This anomalous behavior is likely a manifestation that dilute particles/vacancies in the top-most Landau level form Wigner crystals,which have finite compressibility and can host polarization current.展开更多
Magnetotransport experiments including tilt fields are performed on ultrahigh mobility L-shaped Hall-bar samples of GaAs/AlGaAs quantum wells. The low-temperature longitudinal resistivity （ρxx） data demonstrate tha...Magnetotransport experiments including tilt fields are performed on ultrahigh mobility L-shaped Hall-bar samples of GaAs/AlGaAs quantum wells. The low-temperature longitudinal resistivity （ρxx） data demonstrate that a striking even-odd asymmetric transport exists along the [110] direction at half filling in N ≥ 2 high Landau levels. Although the origin for the peculiar even-odd asymmetry remains unclear, we propose that the coupling strength between electrons within the same Landau level and between the neighboring two Landau levels should be considered in future studies. The tilt field data show that the in-plane field can suppress the formation of both bubble and stripe phases.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.92065104 and 12074010)in part by the Gordon and Betty Moore Foundation’s EPi QS Initiative(Grant No.GBMF9615)to L.N.Pfeifferby the National Science Foundation MRSEC(Grant No.DMR 2011750)to Princeton University。
文摘We study ultra-high-mobility two-dimensional(2D)electron/hole systems with high precision capacitance measurement.It is found that the capacitance charge appears only at the fringe of the gate at high magnetic field when the 2D conductivity decreases significantly.At integer quantum Hall effects,the capacitance vanishes and forms a plateau at high temperatures T≥300 m K,which surprisingly disappears at T≤100 m K.This anomalous behavior is likely a manifestation that dilute particles/vacancies in the top-most Landau level form Wigner crystals,which have finite compressibility and can host polarization current.
基金Supported by the National Basic Research Program of China under Grant Nos 2014CB920904 and 2013CB921702the National Natural Science Foundation of China under Grant Nos 11174340,11174357,91221203 and 91421303+2 种基金the Strategic Priority Research Program B of the Chinese Academy of Sciences under Grant No XDB07010100the Gordon and Betty Moore Foundation through the EPiQS initiative under Grant No GBMF4420the National Science Foundation of MRSEC under Grant No DMR-1420541
文摘Magnetotransport experiments including tilt fields are performed on ultrahigh mobility L-shaped Hall-bar samples of GaAs/AlGaAs quantum wells. The low-temperature longitudinal resistivity （ρxx） data demonstrate that a striking even-odd asymmetric transport exists along the [110] direction at half filling in N ≥ 2 high Landau levels. Although the origin for the peculiar even-odd asymmetry remains unclear, we propose that the coupling strength between electrons within the same Landau level and between the neighboring two Landau levels should be considered in future studies. The tilt field data show that the in-plane field can suppress the formation of both bubble and stripe phases.
