Nanomechanical Field-Effect Magnetometry in Graphene

This presentation will describe our studies of graphene nanomechanical resonators in the quantum Hall (QH) regime. We observe strong magneto-mechanical coupling to de Haas-van Alphen oscillations of magnetization, resulting in oscillatory frequency shifts of up to 1 MHz. This response is over two orders of magnitude larger than the expected response in a ``standard'' torque magnetometry framework. Instead, we find that the electric field-effect modulation of the magnetic energy provides a gradient force without a magnetic field gradient. Modeling of the effect produces excellent agreement with experiment, using only the disorder as a free parameter. We further use this novel mechanism to quantify the many-body exchange interaction of broken-symmetry QH states. This new mechanism may prove to be a useful tool for magnetic studies across low-dimensional materials and in sensing applications.