Physics Colloquium
Artificial Layered Materials: Tailoring Quantum Matter in van der Waals Heterostructures
Rafi Bistritzer
Tel Aviv University
Abstract
The isolation and assembly of atomically thin crystals have transformed our ability to create quantum matter by design rather than merely discover it. By choosing the constituent layers, their stacking arrangement, relative twist angle, dielectric environment, and electrostatic gating, it is now possible to engineer electronic band structures, interactions, and topological properties with unprecedented flexibility.
In this colloquium, I will first provide an overview of the rapidly evolving field of layered materials. I will then describe our recent work on acoustoelectric superlattices, in which surface acoustic waves create highly tunable artificial lattices for two-dimensional electrons, enabling in situ control of minibands and topological transitions. In the final part of the talk, I will discuss the emergence of giant capacitance in graphene-based double-layer quantum Hall ferromagnets. Here, the competition between capacitive charging and Coulomb exchange gives rise to a rich phase diagram characterized by first-order charge-transfer transitions, in which a macroscopic amount of charge is transferred between the layers in response to a small change in bias voltage.
In this colloquium, I will first provide an overview of the rapidly evolving field of layered materials. I will then describe our recent work on acoustoelectric superlattices, in which surface acoustic waves create highly tunable artificial lattices for two-dimensional electrons, enabling in situ control of minibands and topological transitions. In the final part of the talk, I will discuss the emergence of giant capacitance in graphene-based double-layer quantum Hall ferromagnets. Here, the competition between capacitive charging and Coulomb exchange gives rise to a rich phase diagram characterized by first-order charge-transfer transitions, in which a macroscopic amount of charge is transferred between the layers in response to a small change in bias voltage.