Theoretical study of spin decoherence in transition metal dichalcogenides*

Transition metal dichalcogenides (TMDC) have recently emerged as potential candidates to host coherent qubits to realize quantum information technologies in two-dimensional materials platforms [1]. Prospective qubit candidates include quantum dots, valley qubits, and spin defects [2,3,4]. Notably, a recent experimental study reported creation of a localized electron spin by using a carbon radical ion in WS₂, which could be further developed to a spin qubit system [5]. In this study, we theoretically investigate the decoherence time of spin defects in MX₂ TMDC materials (M=Mo, W and X=S, Se, Te). We compute the Hahn-echo decoherence time (T₂) of an electron spin associated with carbon radical ions in TMDC by combining a cluster correlation expansion method (CCE) and density functional theory [6]. We found that the T₂ time of TMDC materials ranges from 1.6 ms to 36 ms, and the longest T₂ time was found for WS₂. We also discuss the microscopic mechanism of the decoherence in TMDC materials by analyzing their spin Hamiltonian terms. Our results show that TMDCs are promising materials to host robust spin qubits with long coherence time, which would be crucial for their potential applications in quantum sensing and quantum information processing.

[1] Liu, X., Hersam and M.C., Nat. Rev. Mater. 4, 669–684 (2019).

[2] Ye, M., Seo, H. and Galli, G., npj Comp. Mater. 5, 44 (2019).

[3] Onizhuk, M. and Galli, G., Appl. Phys. Lett. 118, 154003 (2021).

[4] Kormányos, A. et al., Phys. Rev. X 4, 011034 (2014).

[5] Cochrane, K. A. et al., arXiv:2008.12196 (2020).

[6] Seo, H. et al., Nat. comm. 7, 12935 (2016).