Time-resolved investigation of plasmon mode along interface channels in integer and fractional quantum Hall regimes

The authors investigate here the fundamental charge dynamics of interface quantum Hall (QH) channels, formed at the interface of two QH regions, by using a time-resolved scheme. The measured plasmon mode is delayed and broadened due to the influence of charge puddles formed around the channel. The transport behavior can be understood with a distributed circuit model, which reveals the importance of gate-puddle capacitive coupling on plasmon dissipation. By reducing the puddle capacitance, a high-quality fractional interface channel can be realized.