RII Track-4: Exploring Ferromagnetism in Two-Dimensional Van Der Waals Materials

Clemson University, Clemson SC

Investigators

Abstract

The current silicon-based information technologies start to approach the physical limit set by the speed and density of electronic transistors. To continue the trend of Moore's Law, the hope is the emergent quantum materials because they may shift the information processing paradigm from controlling the electronic transport to manipulating the spin interaction, thereby eliminating charge transfer and heat dissipation, leading to higher speed, smaller device, and better energy efficiency. This transformative technology is known as "spintronics", which requires the coexistence of magnetic and semiconducting properties. Recent discovery of intrinsic magnetism in two-dimensional (2D) semiconductors is considered as a promising candidate system, whose unique properties are correlated to the electron and spin interactions within the crystal lattices, which needs to be understood at the atomic length scale. This project aims to investigate the magnetic spin textures in such 2D materials using transmission electron microscopy (TEM) whose spatial resolution (<1 angstrom) can effectively identify the ultrasmall magnetic characteristics. This work will be performed using the world-class TEM facilities at Brookhaven National Laboratory, where the PI will develop new research expertise and establish long-term collaborations that can greatly enhance the research capacity of Clemson University. The emergence of two-dimensional (2D) materials offers an ideal platform to display exotic physical properties restricted by the quantum confinement, which leads to the groundbreaking discovery of intrinsic 2D magnetism that may have a transformative impact on quantum information technologies. To address the fundamental science questions regarding the charge, spin, and orbital coupling with the crystal lattice in such material systems, the atomistic characterization using transmission electron microscopy (TEM) is essential. The goal of this project is to probe the magnetic spin textures in 2D ferromagnetic crystals and their van der Waals (vdW) heterostructures using TEM-based magnetic imaging techniques. The work will be performed in partnership with researchers at Brookhaven National Laboratory (BNL), which is a worldwide leader in the field of electron microscopy. The PI will employ a unique toolset combining Lorentz microscopy and electron holography to identify the spin textures and elucidate their dependence of extrinsic physical parameters and structural effects in 2D vdW materials with intrinsic magnetic orders. These findings will provide a mechanistic understanding of electron-spin-lattice correlation underpinning the intrinsic 2D magnetic properties and show practical implications for the emerging spintronics applications. This fellowship allows the PI to establish a long-term collaboration between Clemson University and BNL, which, in turn, will strengthen the research activities, expertise, and education for the PI and the whole Clemson community, and thereby enhance the scientific competitiveness, workforce development, and economic growth of the State of South Carolina. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.