Two dimensional atomic crystals under strain

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

Non-Technical Description: Two-dimensional atomic crystals, the building blocks for layered materials, have promising electrical/optical properties that are strongly affected by their structures. Formed through strong chemical bonds, these materials can be atomically thin yet act like a crystal with the ability to bend. It is both interesting and important to understand how the crystal deformation (strain) may modify their electronic and charge transport properties. Based on such understanding, lattice deformation may be used for better electronic properties and to create novel material systems for the study of low dimensional physics. This project studies the impact of strain on the electronic and charge transport properties of two-dimensional atomic crystals in their nanoelectromechanical devices, where strain can be independently tuned and accurately characterized. This project addresses some of the key scientific and technological issues in a highly active research area. It also provides graduate students with research experience both in the PI's Stony Brook laboratory and in national laboratory settings. Undergraduate students drawn from the diverse student body of Stony Brook University and high school students from the greater New York region will be brought in to play active roles in the research. To widen the general public interest in sciences, the research team will broadcast original videos on student research in the lab, and introductions to basic experimental research techniques. Technical Description: Two-dimensional atomic crystals are formed through strong chemical bonds which render them flexible and stretchable in nature. As a result, lattice deformation may be utilized to achieve more favorable electronic properties and to create novel material systems for the study of low dimensional physics. The project is developing a nanoelectromechanical resonator device scheme with large strain tunability and transport measurement capability, through which both the mechanical and charge transport properties are studied and correlated. This approach is applied to two-dimensional atomic crystals including (but not limited to) single- and bi-layer graphene, phosphorene, and ZrTe5. The research team focuses on the impact of mechanical deformation (including uniaxial, shear and triaxial strains) on charge carrier scattering, valley polarization, band structure tuning, and topological transitions in these two-dimensional materials. The project advances the understanding in the fundamental physical properties of novel two dimensional materials and in modulating their electronic properties to study novel two-dimensional physics. Modification of lattice structure and/or symmetry can effectively create new artificial material systems which allow the study of novel physical phenomena inaccessible in conventional materials. This proposal, which focuses mainly on charge transport studies, directly addresses fabrication and measurement of the electronic devices. Hence, it further advances the concept of strain-tunable electronics beyond the previous efforts which are mainly based on optical and local probe studies. 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.