Research

Liu Research Group focuses on the synthesis, optical and electric measurements of two-dimensional materials and heterostructures. The group uses analytical scanning transmission electron microscopy, electron energy-loss spectroscopy, and cathodoluminescence spectroscopy to investigate the fundamental structure-property relationships on the nanoscale for novel electronic, photonic, and polaritonic properties.

Novel 2D materials and heterostructures

We are interested in the synthesis and fabrication of 2D materials and heterostructures including atomically thin van der Waals materials and ultrathin membranes formed by conventional 3D materials such as complex oxides.  We examine the optoelectronic, ferroelectric, and magnetic properties arising from the interfacial electronic coupling in these materials.

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          Automatically thin heterostructures                                                  Moire van der Waals materials

Transmission electron microscopy and spectroscopy

We are interested in using atomic scanning electron microscopy, electron energy loss spectroscopy, and cathodoluminescence spectroscopy to understand the optical properties of 2D materials on the nanoscale. The results obtained from electron nanoscopy will be correlated with complimentary optical spectroscopy measurements to provide a crucial understanding to enable the precise control of their optical properties down to the atomic scale for nanophotonics and quantum optics.

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Electron probing quantum defects in 2D materials.                            Nano-optics with electrons

Polaritons in 2D materials

We are interested in polaritons, which are quasiparticles resulting from the hybridization of light with dipole-active excitations, such as optical phonons and excitons, in low-dimensional materials. We explore new polaritonic materials and utilize them in nanophotonic devices.