Solid-state qubits in moire superlattices

Abstract

Qubits are the fundamental units in quantum computing, but they are also pivotal for advancements in quantum communication and sensing. Currently, there are a variety of platforms for qubits, including cold atoms, superconducting circuits, point defects, and semiconductor quantum dots. In these systems, each qubit requires individual preparation, making identical replication a challenging task. Constructing and maintaining stable, scalable qubits remains a formidable challenge, especially for solid-state qubits. The race to identify the best one remains inconclusive, making the search for new qubits a welcome endeavor. Our study introduces moiré superlattices of twisted bilayer materials as a promising platform for qubits due to their tunability, natural patterns, and extensive materials library. Our first-principles calculations reveal that when the twist angle between the two layers is sufficiently small, these materials foster identical, localized quantum wells within the moiré superlattices. Each quantum well accommodates a few dispersionless bands and localized states, akin to the discrete energy levels of an alkali atom. Existing experimental techniques allow for individual initialization, manipulation, and readout of the local quantum states. The vast array of 2D materials provides a multitude of potential candidates for qubit exploration in such systems. Due to their inherent scalability and uniformity, our proposed qubits present significant advantages over conventional solid-state qubit systems.