Quantum transport in quantum Hall antidots
Quasiparticles of the fractional quantum Hall effect (FQHE) possess nontrivial anyonic exchange statistics, inviting the possibility of novel quantum information devices based on the braiding of individual quasiparticles. QH antidots, allowing control over individual quasiparticles, are promising systems for studying anyon exchange/braiding. In a QH antidot, QH edge modes encircling a small void inside the 2-dimensional electron system (2DES) form quantized energy levels due to quantum confinement, mimicking an artificial atom. Individual quasiparticles of the QH fluid can then be added to, extracted from, or transferred between QH antidots through tunneling. We study QH antidot-based artificial atoms and artificial molecules, focusing on the possibility of observing anyon exchange/braiding in these systems. High quality hBN-encapsulated graphene and suspended graphene QH antidots are studied. Compared to GaAs-based 2DEG, the Dirac electrons in graphene allows 1-2 orders of magnitude larger energy scales, allowing robust confinement of QH edge modes, hence building of complicated and functional multi-dot devices.
The “World of Anyons” demos (supported by NSF DMR 2104781)
Here is a demo of anyon interference made by Daniel Potemkin using Godot engine.
Download the demo and experience of the strange world of anyons! AnyonDemo_Executable
Technological development of nanofabrication allows creation of increasingly fine/small nanostructures with sizes approaching single-digit nanometer. With the top-down approach of nanolithography, we aim to create complex electrostatic potential profiles which allow modification of the periodicity and symmetry of the 2D lattices, hence achieving on-demand band structure engineering. These “artificial crystals” may allow studies of electronic properties which are otherwise difficult to achieve in naturally-formed materials.
2D Crystals Under Strain
Two dimensional atomic crystals (2DACs), owing to their structural flexibility and elasticity, are ideal systems for “strain engineering” through which their electronic and optical properties may be tailored. Understanding and controlling the impact strain on the 2DACs promise to bring new understanding to mesoscopic physics as well as novel material/device applications. Despite the highly rewarding potential, studies of the strain effect on 2DACs have been mostly limited to theoretical, local probe and optical probe techniques. Our efforts focus establishing an effective and independent tuning knob for the strain, through which intrinsic charge transport properties of the 2DACs under strain can be studied. We have demonstrated a tunable graphene mechanical resonator on flexible substrate, allowing accurate characterization of strain through mechanical resonance, and transport characterization of graphene under fine-tuning of strain. We apply similar technique to other 2DACs, to understand the impact of strain o n their electronic/transport properties.