Band structure engineering of moirŽ van der Waals heterostructures with high pressure
Abstract
The ability to create designer heterostructures comprising various atomically-thin van der Waals (vdW) materials holds significant promise for realizing new electronic properties in a highly tunable condensed matter platform. The properties of these vdW heterostructures can be modified using a number of experimental knobs, including the twist angle between neighboring crystals and their interlayer hybridization strength. The aim of this proposal is to dynamically tune the interlayer electronic coupling between vdW crystals by reducing their interlayer spacing with hydrostatic pressure. In vdW heterostructures featuring a moirŽ pattern, the amplitude of the superlattice potential can be directly modified with pressure. The proposed study will focus on the investigation of two prototypical moirŽ van der Waals heterostructures under high pressure Ð graphene aligned with hexagonal boron nitride, and twisted bilayer graphene. By tuning the moirŽ potential with pressure, it will be possible to engineer a variety of novel electronic states of matter Ð including those featuring strong correlations and non-trivial band topology Ð with unprecedented tunability. Additionally, pressure can drive both reversible and irreversible crystal structure transitions in these samples. This technique will significantly expand the scope of vdW heterostructures to include new crystal structures and electronic band structures which do not exist at ambient pressure. Previous work by the PI established the ability to apply pressures of up to 3 GPa using piston cylinder cells. The work proposed here will develop new techniques to measure quantum magnetotransport of arbitrary vdW heterostructures at pressures of up to 30 GPa in diamond anvil cells (DAC), which feature the ability to continuously change the pressure at low temperature. The high pressure techniques developed in this work can further be applied to a wide variety of vdW heterostructures, and will lead to the realization of new electronic device functionalities.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 09, 2020
- Source ID
- W911NF2010211
Entities
People
- Matthew Yankowitz
Organizations
- Army Contracting Command
- United States Army
- University of Washington