26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Artificial Quantum Matter

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Poster AIP | Quantum Science and Technology (QST)

Description

Artificial crystals, formed by imposing spatially periodic potentials onto existing material platforms, provide a powerful route for designing and controlling electronic properties beyond those available in natural systems. Moiré superlattices in twisted two-dimensional (2D) materials have recently emerged as a prominent example, hosting correlated insulating states, superconductivity, and other strongly interacting quantum phases in graphene-based systems. However, moiré lattices are fundamentally constrained by the symmetry of the underlying 2D crystals and the twist angle between layers, which can introduce non-uniform long-range strain and limit lattice uniformity. In addition, the strength of the modulation potential is largely fixed once the device is fabricated, restricting post-fabrication tunability.
To overcome these limitations related to strain and device flexibility, we present an alternative and highly tuneable approach to artificial quantum matter based on imposing spatially periodic electric potentials using patterned metallic gate architectures. Such gate-defined superlattices enable the realization of artificial crystals with arbitrary lattice symmetries, tuneable lattice constants, and controllable modulation strengths, while remaining compatible with a wide range of material platforms, including conventional semiconductors and van der Waals heterostructures.
We fabricate these devices through a sequence of advanced nanofabrication steps, ranging from mechanical exfoliation of high-quality flakes to full device assembly and packaging. To enhance electron mobility in the transport channel and reduce contact resistance, optimized forming-gas annealing and precisely controlled reactive ion etching processes are employed. Finally, using magneto-transport and radio-frequency capacitive measurements at ultralow temperatures, we investigate emergent quantum phases arising from engineered band topology, electron–electron interactions, and magnetic-field-induced effects.