Two-Dimensional Quantum Materials and Heterostructures

Summary

Two-dimensional (2D) layers just one atom thick can be stripped from certain materials, such as graphene. The individual layers from one or more of these materials can then be restacked to create cage-like quantum heterostructures, which possess novel quantum properties. Incorporating magnetism into such a structure at room temperature could enable direct control of electron spin polarization in the transistor geometry. We are working to combine 2D semiconductors and magnetic insulators as an early step toward creation of magnetic semiconductor heterostructures for spintronic devices. Along with proving the heterostructure concept, success in combining the two materials supports a subsequent goal, fabrication of a nanostructure consisting of a superconductor, semiconductor, and magnetic insulator. Achievement of these two goals will provide a fundamental building block for spintronics, address a vital materials challenge in the pathway to quantum computing, and potentially allow for integration of processing and storage technologies in a single device platform.

Figure 1. Magnetic van der Waals tunnel junction incorporating ultrathin chromium trihalides. (A) Schematic illustration of the device. (B) Normalizedtemperature-dependent dc resistance of CrX3(X=I, Br, and Cl) at constant current of 0.1 nA.Insetsshow schematics of the spin-dependent tunnel barrier forAFM and FM interlayer coupling. Red and blue arrows indicate spin orientation and are used throughout. Original illustration from PNAS Publications.