Negative nonlocal vicinity resistance of viscous flow in a two-dimensional electron system

Abstract

We perform a quantum transport study of Hall viscous liquid in multiterminal narrow Hallbar devices of a high-mobility two-dimensional electron system (2DES) in GaAs/AlGaAs heterostructure. In the nonlocal transport measurements of vicinity geometry under magnetic fields $(B)$, we observe that the absolute negative magnetoresistance $({R}_{xx})$ value $({R}_{\text{min}}<0)$ and the corresponding magnetic field $({B}_{\text{min}})$ are both inversely proportional to the adjacent Hallbar arm distance $(L)$. The occurrence of negative resistance is dependent on the characteristic lengths of the devices and the electron flow direction under $B$-fields. The minimal resistance ${R}_{\text{min}}$ occurs when the cyclotron radius ${R}_{C}$ approximates $L$. Multiples of high-order ($n\mathrm{th}$-order) ${R}_{\text{min},n}$'s persist from low to high magnetic fields in a large sample size of $L=5\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{m}$. Our experimental study reveals the transport behaviors in the vicinity regime, where the negative resistances depict viscous electronic flows in the high-mobility 2DES. In addition, the negative and high-order minimal resistances expand to a magnetic field of several kGs.