Thomas Richichi $^{1,2}$, Morgan Sherer$^2$, Arthur Barnard$^2$
$^1$North Seattle College $^2$Molecular Engineering and Material Science Center, University of Washington
Engineering and tuning the electronic and magnetic properties of vdW heterostructures is vital to using and understanding 2D materials. Stacking engineered ferroelectricity in bilayer hexagonal boron nitride is intrinsically dependent on the stacking order of the monolayers relative to each other and both translations and rotations of one layer relative to the other have shown that domains of ferroelectricity can be manipulated. Similarly the antiferromagnetic properties of CrI$_3$ have been shown to have dependencies on the stacking order and experimental confirmation of irreversible antiferromagnetic to ferromagnetic switching has been reported. Due to the dependence on relative displacements and rotations of each monolayer relative to the others within a device, we hypothesize that shear forces applied to the topmost layer could lead to shear deformations in the device that trigger transitions between different ferroelectric (ferromagnetic) states in hBN (CrI$_3$). To investigate the hypothesis we devise a method of applying shear forces to vdW devices by means of organic microstructures of spherical and cylindrical geometries. The primary polymer under investigation is poly(dimethyl)siloxane (PDMS), due to its rapid production time, optical transparency, tunable stiffness and ease of access. We consider possible production methods to create PDMS microstructures with the desired features. We compare several methods of microstructure fabrication, using a PDMS double casting technique and outline modes of failure based on different parameter values. In addition to fabrication techniques, we also simulate the experimental setup by means of a COMSOL simulation. In the simulation we model the PDMS microstructure and device to probe the stress through the microstructure and the forces applied to the device as a function of lateral pillar displacement.
Thomas Richichi is a computer science–focused researcher with a strong foundation in physics and mathematics, with experience in scientific computing and simulation (e.g., COMSOL, MATLAB, and Python). His first experience with research was with the Molecular Engineering and Material’s Science Center (MEM-C) at the University of Washington, where he worked on simulating and designing nanostructures for experiments in material’s science. Motivated by complexity, problem-solving and leveraging technology, he is pursuing his BS in Computer Science, with the aims of advancing scientific research by helping to create the tools of the future.
This work is supported by the National Science Foundation through Materials Research Science & Engineering Center (MRSEC) award DMR-2308979