We study a large variety of interesting materials including superconducting, magnetic, nano, and emergent topological quantum materials.
We start from single crystal synthesis, to structure phase determination, and to electronic transport, magnetic, and thermal properties characterizations, at our two labs and UA user facilities. For crystals grown in our lab, please see this page🔗. For lab equipment and facilities, please see this page🔗.
Topological Materials
The theory of topological phases and phase transitions, which is the subject of the 2016 Nobel Prize in Physics, has bridged particles in high energy physics and electronics in crystalline solids. Dirac, Weyl, and Majorana fermions have found counterparts in the emergent topological quantum materials including topological insulators/Dirac semimetals, Weyl semimetals, and topological superconductors, respectively. These emergent quantum materials, possessing linearly dispersed relativistic energy bands in momentum space protected by certain symmetries, have enormous potential to provide new insights into a range of physical properties displayed by electrons in crystals, offering the foundation for new generations of devices.
Our research on these materials mainly focuses on discovering new topological quantum materials, finding their exotic electronics properties owing to the non-trivial band topology, clarifying the interplay between topology, symmetry, magnetism, electronics correlations, etc. For example the magnetic topological semimetal candidate LnSbTe (see figure).
Coexistence of Dirac fermion, magnetism, electronic correlations in SmSbTe [Back cover, Advanced Quantum Technologies 4, 2100063 (2022)]
Low Dimensional Materials
Owing to quantum confinement effect on electrons, phonons, and magnetons, as well as enhanced surface-to-bulk ratio, materials in low dimensions exhibit drastically modified properties. Additionally, with reduced size, materials are more tunable by an external electric field, strain, etc. Furthermore, low dimensional materials also enable heterojunctions that display a wide spectrum of novel properties. Examples include the fantastic graphene, monolayers of transition metal dichalcogenide (TMD) semiconductors that possess direct bandgap and activated valley degree of freedom, and the recent breakthroughs in 2D magnets.
Our research on low dimensional materials focuses on novel properties in new or old low dimensional materials, obtained by mechanical exfoliations or CVD/PVD growth. The two emphases are topological materials in low dimensions, and the 2D magnet with high ordering temperatures.
Bringing together dimensionality effect and topological physics, new phenomena may occur such as new quantum state due to confinement, and new transport from surface state (see figure).
Unusual surface state in ZrSiSe probed by transport on nano flakes [supplement cover article, Nano Lett 21, 4887 (2021)].
Magnetic Materials
Magnetic materials play a crucial role in a wide range of technological applications, from everyday devices like hard drives and credit cards to advanced medical imaging and power generation systems. The phenomenon of magnetism has been known since ancient times, but the mechanism of magnetism was understood after the development of quantum mechanics. Lots of the concepts are still underdevelopment, and new phenomena relevant to magnetism are still emerging, such as quantum spin liquid and magnetic skyrmions.
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Our research on magnetism has a few focuses, such as layered/2D or 1D magnetism with high ordering temperature (ideally above room temperature), new materials showing topological spin textures, and exotic transport phenomena due to the coupling between charge, spin, and lattice. A few examples include MPX3 (M = metal, X = S or Se) and Mn2-xZnxSb