Prof. Cheng Gong joined the Department of Electrical & Computer Engineering at University of Maryland, College Park as an Assistant Professor in 2019 and was promoted to Associate Professor with tenure in 2024. His research focuses on 2D quantum materials and devices. He is a recipient of the IUPAP Young Scientist Prize in Semiconductor Physics 2020. In 2022, Prof. Gong won UMD’s top recognition “Invention of the Year”, American Chemical Society’s “Maryland Chemist of the Year”, and “Governor’s Citation” from Governor Hogan’s office. Prof. Gong is a recipient of NSF CAREER Award in 2024.
Presentation Title:
Van der Waals heterostructure multiferroics
Presentation Abstract:
Two-dimensional (2D) layered van der Waals (vdW) ferroics (e.g., ferromagnets [1,2] and ferroelectrics [3]) are atomic-thin crystalline flatlands with long-range ferroic order, underpinning numerous new physical phenomena and novel device functionalities that non-ferroic 2D materials cannot enable. However, ferroic orders in 2D systems are prone to destruction: In 2D systems, ferroelectric order [1] tends to be destructed by enhanced depolarization fields and magnetic order [2] tends to be suppressed by enhanced thermal fluctuations. Simultaneously attaining more than one ferroic order in a 2D platform thus appears even more challenging [4].
In this talk, I will present our work on the integration of long-range magnetic and ferroelectric orders into 2D vdW heterostructures by assembling ferroelectric and magnetic vdW layers. We unambiguously probe the inter-ferroic magnetoelectric coupling by demonstrating non-volatile electric control of 2D magnetism [5,6]. By systematic experiments on samples of various thicknesses, we reveal short-range interfacial interaction underlying the magnetoelectric coupling in vdW heterostructure multiferroics [6]. For the first time, we build all-vdW multiferroic tunnel junctions [7], consisting of two vdW magnetic layers separated by a vdW ferroelectric spacer with full tailorability on each constituent layer, and demonstrate four-state electrical resistance by toggling ferroelectric polarization and magnetization orientations, respectively. The development of vdW multiferroic heterostructures and devices holds tantalizing possibilities for designer magnetoelectric quantum heterostructures and compact energy-efficient spintronic devices.
1. C. Gong et al. Nature 546, 265–269 (2017).
2. C. Gong, X. Zhang. Science 363, eaav4450 (2019).
3. Q. Wang, et al. Matter 5, 4425-4436 (2022).
4. C. Gong et al. Nature Communications 10, 2657 (2019).
5. S. Liang et al. Nature Electronics 6, 199–205 (2023).
6. S. Liang et al. Nature Electronics 9, 23–32 (2026).
7. T. Xie et al. Nature Nanotechnology 21, 366–373 (2026).