Wang Lab of Quantum Matter

The search for emergent novel states in quantum materials with a kagome lattice is a wide-open frontier in condensed matter physics. The interplay of frustrated geometry, electron correlations, and non-trivial topology paves the way for discovering new phases of quantum matter, such as topological magnets and topological semimetals. Further advances in the research on KAMs hinge on three key challenges:

• Precisely detecting electronic structures imposed by electron interactions.
• Identifying the fundamental origin of emergent quantum phases, such as charge-order and topological phases.
• Discovering new states and phases via new materials.

The key to addressing these challenges is to directly visualize these emergent quantum at the atomic scale. Combining beyond state-of-the-art scanning tunnelling microscopy (STM) under magnetic fields and ultra-low temperatures, you will aim to detect the novel emergent quantum phases in KAMs, such as the 135 kagome metal and the 166 kagome magnet. You will explore the connections of these quantum states to other modern quantum matter such as Weyl semimetals, topological magnets, and topological superconductors. These efforts will significantly expand our knowledge of quantum matter physics in recently discovered quantum materials, advancing the field of condensed matter physics.

This area represents an entirely new and blooming field of research, providing vast unexplored territories and an excellent opportunity to start a research career. Identifying a topological quantum magnet could profoundly impact quantum sciences and future spintronics applications. This project aims to make new scientific contributions, entering one new research area in condensed matter physics and likely leading to high-quality publications. The project will also involve collaboration with other universities, such as the University of Warwick and the University of Washington St Louis.

The Quantum and Soft Matter Theme at Bristol has extensive low-temperature facilities including cryostats, magnet systems, and a dedicated helium liquefier. The condensed matter physics department is world-leading in research on experimental quantum materials and a national centre. 

The equipment and the labs:
ATLAS is the dilution fridge based, 9 Tesla STM (on which our SJTM technique was originally developed) which is now under construction at the HH Wills Lab, Bristol University. The STM is used to study cleaved samples.

Intrinsic topological superconductivity (ITS) is an unprecedented phase of electronic matter that stands at the frontier of modern quantum matter. Intrinsic topological superconductivity has been sought without success since the early 1960s. ITS promise both cutting-edge science and revolutionary quantum technology. Key signatures for an ITS include the existence of odd-parity electron pairing, superconductive topological surface bands, and, when time-reversal symmetry (TRS) is broken, persistent chiral supercurrents with speed flowing along every surface. None of these characteristics has ever been detected. Until recently, new candidate ITS materials have been discovered, and innovative Spectroscopic Imaging Scanning tunneling Microscopy (STM) techniques designed to reveal the key characteristic of ITS has been developed.
You will exploit these exciting opportunities by using direct atomic-scale visualization of ITS fingerprints, such as odd-parity pairing, and/or superconductive topological surface bands, and/or persistent chiral supercurrents. Thus, after decades of anticipation, your goal is achieve detection of the fundamental characteristics of three-dimensional ITS. The consequences will be sharp clear provenance of which materials actually are ITS, distinct revelation of which ITS phenomena occur in nature, and eventual identification of the ITS that are most ideal for quantum technology.
You will focus on candidate materials 2M-WS₂, among others. Using ultralow temperature and high magnetic field STM at the Universities of Oxford and Bristol, you will pursue three scientific objectives. (1) Demonstrate the presence of odd-parity superconducting pairing. (2) Momentum-space visualization of the topological surface band. (3) Detect a flowing chiral surface supercurrent when TRS is broken. Your ultimate goal will be to confirm the presence and explore the unprecedented physics of intrinsic topological superconductivity.

The equipment and the labs:
MINERVA and GEMINI are fourth-generation UHV, 14 Tesla, millikelvin STMs that are fully operational at the Beecroft Building, Oxford University. ATLAS is the dilution fridge based, 9 Tesla STM (on which our SJTM technique was originally developed) which is now under construction at the HH Wills Lab, Bristol University. All three STMs are used to study cleaved samples.