Detecting Strain Effects Due to Nanobubbles in Graphene Mach–Zehnder Interferometers

Abstract

Herein, the effect of elastic strain on a Mach–Zehnder (MZ) interferometer created by graphene p–n junction in quantum Hall regime is investigated. It is demonstrated that a Gaussian‐shaped nanobubble causes detuning of the quantum Hall conductance oscillations across the p–n junction, due to the strain‐induced local pseudo‐magnetic fields (PMFs). By performing a machine‐learning‐based Fourier analysis, the nanobubble‐induced Fourier component from the conductance oscillations originating from the external magnetic fields is differentiated. It is shown that the detuning of the conductance oscillations is due to the altered pathway of quantum Hall interface channels caused by the strain‐induced PMFs. In the presence of the nanobubble, a new Fourier component for a magnetic flux appears, and the corresponding MZ interferometry indicates that the enclosed area is reduced by half due to the strain‐mediated pathway between two quantum Hall interface channels. In the findings, the potential of using graphene as a strain sensor is suggested for developments in graphene‐based device fabrications and measurements technologies.