The physics of quantum materials can be often understood by simply measuring their resistivity as a function of carrier density, electric field, temperature, and magnetic field. In our lab, we are establishing low-temperature and low-noise magnetotransport measurements. Some of our previous results employing this technique are listed below:

• Nature Communications, 13, 5967 (2022)

• Nature Communications, 13, 1668 (2022)

• Nano Letters, 21, 6, 2544-2550 (2021)

• Nature Communications, 9, 919 (2018)

• ACS Nano 11 (6), 6355-6361 (2017)

• Nature Communications, 7, 12391 (2016)

• ACS Nano, 8 (8), pp 8174–8181 (2014)

Quantum materials have a variety of properties which we are excited about. But what if we take two or more materials and combine them together to create new artificial materials which did not exist before? 2D materials are especially good for those purposes because they are atomically flat and do not have dangling bonds, making interactions between different materials stacked together very strong. We are pursuing the idea of combining topological insulators, magnetic materials, and superconductors in 2D heterostructures. The image on the left demonstrates a triangular lattice of polarization in twisted h-BN.

• https://arxiv.org/abs/2301.03759 (2023)

• https://arxiv.org/abs/2212.14140 (2022)

• Nano Letters, 16 (9), 5792-5797 (2016)

We employ this technique to generate very high electric fields and carrier densities on the surfaces of low-dimensional materials to modulate their electronic, magnetic, and optical properties and induce phase transitions between different quantum states of matter. You can read some of our previous publications about applications of this technique to various 2D materials below:

• Nature Communications, 9, 919 (2018)

• ACS Nano 11 (6), 6355-6361 (2017)

• Nano Letters, 17 (8), 5056-5063 (2017)

• Nature Communications, 7, 12391 (2016)

Scanning probe microscopy (SPM) is a technique that is routinely used to measure various properties of 2D materials. We are interested in visualizing potential landscapes, charge distribution, and conductivity changes in quantum materials with SPM. The image on the left demonstrates imaging of chiral edge states in topological magnet MnBi₂Te₄ with Microwave Impedance Microscopy (collaboration with Prof. Yong-Tao Cui, UC Riverside). Some of our publications employing SPM are listed below:

• https://arxiv.org/abs/2212.14140 (2022)

• Nano Letters, 21, 6, 2544-2550 (2021)

• ACS Nano, 9 (4), pp 4611–4620 (2015)

Transmission electron microscopy (TEM) allows us to directly visualize crystal lattices with atomic resolution. For example, the image on the left demonstrates a distorted lattice of ReS₂, an anisotropic 2D semiconductor. We are interested in this technique and are looking at other ways to probe quantum matter with high-precision electron and ion microscopy. Some of our previous results below:

• ACS Nano, 14, 1, 524–530 (2019)

• ACS Nano 11 (6), 6355-6361 (2017)

• Nature Communications, 7, 12391 (2016)

• 2D Materials, Volume 2, Number 4 (2015)

• ACS Nano, 9 (4), pp 4611–4620 (2015)