Song Lab

Welcome to Song Lab!

We are a new research group focusing on exploring novel 2D quantum materials and their van der Waals heterostructures. We are particularly interested in studying exotic 2D magnetism, 2D superconductivity, and topology by using various techniques, such as nanodevice fabrication, magneto-optics, quantum transport, thermoelectrics, optoelectronics, optical spectroscopy and microscopy.

Research Highlights

2D magnetism & moiré engineering

2D magnet chromium triiodide (CrI3) exhibits unique layer-dependent magnetism and stacking-dependent interlayer exchange interactions. Changing the layer stacking from monoclinic to rhombohedral can switch the interlayer magnetic coupling, and thus the magnetic ground state, from antiferromagnetic (AFM) to ferromagnetic (FM). In twisted CrI3, we observe the coexistence of AFM and FM domains with periodic patterns, revealing moiré magnetism in magnetic moiré superlattices.

Van der Waals spintronics

The recent discovery of atomically thin magnetic vdW materials has created new opportunities to explore 2D magnetism and vdW spintronics. For example, giant tunneling magnetoresistance based on the spin filtering effect in CrI3, pressure tuning of interlayer magnetism, switching of magnetic states via layer stacking, spin-photovoltaic effect, voltage control of vdW magnetic tunnel junctions, and magnetic proximity effect in magnetic vdW heterostructures.

2D superconductivity and topology

Monolayer tungsten ditelluride (WTe2) is so exotic that it hosts superconductivity and nontrivial topology in a single crystalline material. 2D superconductivity occurs at an unusually low carrier density that can readily be induced through electrostatic doping. It undergoes superconductor-insulator transition, and becomes quantum spin Hall insulator at charge neutrality, which survives up to 100 K. With the increasingly advanced nanofabrication techniques, quantum devices based on WTe2 and 2D magnets provide an exciting platform for exploring the interplay between topology, correlations, and magnetism, as well as engineering new quantum phases in 2D systems.