Substrate-controlled dynamics of spin qubits in low dimensional van der Waals materials

Abstract

We report a theoretical study of the coherence dynamics of spin qubits in two-dimensional materials (2DMs) and van der Waals heterostructures, as a function of the host thickness and the composition of the surrounding environment. We focus on MoS2 and WS2, two promising systems for quantum technology applications, and we consider the decoherence arising from the interaction of the spin qubit with nuclear spins. We show that the Hahn-echo coherence time is determined by a complex interplay between the source of decoherence in the qubit host and in the environment, which in turn determines whether the noise evolution is in a classical or quantum mechanical regime. We suggest that the composition and thickness of van der Waals heterostructures encapsulating a qubit host can be engineered to maximize coherence times. Finally, we discuss how quantum sensors may be able to probe the dynamics of the nuclear bath in 2DMs.

Dielectrics for Two-Dimensional Transition-Metal Dichalcogenide Applications

“…The nuclear spins of both the active 2D semiconductor and adjacent dielectric layers can also be equally important. In 2D WS 2 , qubit dynamics are predicted to be completely determined by adjacent dielectric nuclear bath (Figure c) …”

“…Copyright 2019 Springer Nature. (c) Reprinted with permission from ref . Copyright 2021 AIP Publishing.…”

Quantum emitters and detectors based on 2D van der Waals materials

“…[115][116][117][118][119] The exercise of control over such qubit systems can be achieved via electron spin resonance, AC electric fields, magnetic fields and nearby impurities. In addition, spin-valley qubits 117 and heterostructure formation 120 from monolayer TMDs embedded with spin qubits can enhance the coherence time. However, these long coherence times are yet to be demonstrated.…”

PyCCE: A Python Package for Cluster Correlation Expansion Simulations of Spin Qubit Dynamics

“…For example, results of the CCE method show excellent agreement with experiments for bismuth [19,20] and phosphorous [21] donors in Si, the nitrogen-vacancy (NV) center in diamond, [22] and divacancies in 4H-SiC, both axial [23,24] and basal. [25] The CCE method has also been used to predict properties of novel materials, such as 2D platforms for spin qubits, [26,27] and to conduct a general screening of potential qubit hosts over a wide range of materials. [28] However, software implementations of the CCE method are not readily accessible and hinge on in-house developments, which lack openness and transferability.…”