Speaker
Description
Artificial electronic crystals provide a route to creating designer quantum systems in which lattice geometry, band structure and interaction strength can be controlled electrically. We recently demonstrated this approach in an electrostatically defined triangular lattice, where continuous tuning of the periodic potential transforms a two-dimensional electron gas into graphene-like and kagome-like electronic systems [1].
Here we extend this concept to square lattices and explore the orbital physics that emerges in the strong-modulation regime. A sufficiently strong periodic potential transforms the two-dimensional electron gas into an array of coupled quantum wells that can be viewed as artificial “2D atoms” [2]. Unlike conventional atoms, these systems possess a distinct two-dimensional shell structure, with a non-degenerate 𝑠-like ground state followed by degenerate 𝑝𝑥- and 𝑝𝑦-like excited states. We present preliminary magnetotransport measurements of electrostatically defined square lattices as a function of carrier density, lattice potential and magnetic field. We observe transport features associated with the formation of the artificial lattice, including insulating states at low magnetic fields and periodic behaviour at higher fields.
The combination of tunable orbital structure, quasi-one-dimensional electronic bands and enhanced Coulomb interactions makes these artificial square lattices a promising platform for exploring correlated multi-orbital physics.
References
[1] D. Q. Wang et al., Nature Physics (2026).
[2] Z. Krix and O. P. Sushkov, (personal communication, December 4, 2025).