Macroscopic Quantum Tunneling Devices for Nanoscale Attonewton Force Sensing

The precision enabled by ultra-high vacuum, low temperature scanning tunneling microscopy for atomic manipulation has allowed the design of nanostructures that exhibit quantifiable quantum dynamics. This work presents a novel nanoscale probe of atomic-scale forces and enables new detection methods of the energy landscape in a Fermi gas. In a two-dimensional electron gas, the geometry of the boundaries on the surface will produce uniquely non-local alterations in the electronic wave function. By creating a device in which a single atom or molecule can macroscopically tunnel between degenerate states in a double potential well, we are able to detect quantum forces that break the degeneracy by measuring an asymmetry in the tunneling rates between each side. Our new method of two-dimensional nanoscale force measurement is able to detect forces with attonewton sensitivity, and the device’s design permits the probing of quantum forces due to proximal nanostructures with atomic resolution. Designer boundary conditions can amplify the measured forces and further illustrate the non-local nature of quantum force fields. We will discuss ways to extend device sensitivity even further, below the attonewton level.