Welcome to the homepage of our group led by Prof. Ying-Shuang Fu at Huazhong University of Science and Technology!
We are an experimental research group working in the field of condensed matter physics. Our research mainly focuses on the study of electronic properties of low dimensional systems with novel quantum behaviors, such as magnetism, superconductivity, correlated states, and topological states of matter. Our experimental instruments include molecular beam epitaxy and scanning tunneling microscopy and atomic force microscopy in ultra low temperature and high magnetic field. Our lab is located in the Science Building at the middle of the western campus of our university.
Research Interests:
Molecular beam epitaxy growth of low dimensional quantum materials
Electronic properties of correlated states in low dimensional systems
Electronic properties of topological states of matter
Spin-resolved spectroscopic imaging of magnetism in low dimensions
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Research overview:
Quantum systems with reduced dimensions, referred to low dimensional quantum materials, host a wealth of unusual physical phenomena that are more prominent than their three-dimensional counterparts. In low dimensions, electron movement are confined, resulting in quantization of single-particle electronic states. This not only can modulate the physical properties of quantum systems, but also promotes electron correlation effect, as a result of the decreased electron screening and enhanced Coulomb interactions. Moreover, inversion symmetry breaks at the interfaces of low dimensional systems. This, in conjunction with the spin-orbital coupling, may generate electronic states with topological characters. Our research interests lie in the synthesis of artificially designed low dimensional quantum materials with with molecular beam epitaxy (MBE), and characterization of the novel electronic behaviors in those quantum systems with high energy and spin-resolved scanning tunneling microscopy (STM) at atomic scale. Our research interests include:
1. Molecular beam epitaxy growth of low dimensional quantum materials
The synthesis of high quality low dimensional systems is an essential first step for characterizing their novel properties. Through controlling the thermal dynamics and kinetics of material growth on surfaces, we grow various low dimensional quantum structures with designed functions with molecular beam epitaxy (MBE) in a clean ultrahigh vacuum environment. More importantly, MBE can even grow metastable structures that are inaccessible with conventional methods for growing three dimensional crystals, opening up a new pathway towards finding new materials.
2. Electronic properties of correlated states in low dimensional systems
In low dimensional systems, electronic states at Fermi level are highly susceptible to external perturbations, such as electron-phonon interaction, electron-electron interaction, etc. This results in a wealth of emergent correlated electronic states, including charge density wave, spin density wave, superconductivity and correlated insulators. We characterize those novel emergent states with scanning tunneling spectroscopy (STS) at ultralow temperature and high magnetic fields. The low temperature allows the correlated physics to emerge and suppresses thermal broadening for achieving high energy resolution tunneling spectroscopy. The high magnetic field tunes the orbital and spin motion of electrons, acting as a viable knob for controlling the exotic quantum systems.
3. Electronic properties of topological states of matter
Topological materials feature nontrivial topology in their electronic band structure, revolutionizing the traditional view of phase transitions. The topological materials contain include a large family of material class, including topological insulators, topological semimetals, Weyl semimetals, and topological superconductors, etc. Largely driven by theoretical predictions, we investigate desired topological properties and experimentally justify predicted new topological materials. Since the topological systems involve spin characters, we aim to bring spin resolved STS into those characterizations.
4. Spin-resolved spectroscopic imaging of magnetism in low dimensions
Magnetic orders in low dimensional systems tend to be destroyed by quantum and thermal fluctuations. In the presence of magnetic anisotropy, the magnetic orders can survive in van der Waals (vdW) crystals at single layer limit. Those intrinsic magnetic order bolstered extensive interest in identifying new vdW magnetic materials and tuning such magnetic order. We use spin-resolved STM to investigate the intrinsic magnetic order, which is capable of resolving ferro-, antiferro-, as well as non-collinear magnetic order at atomic scale.
