Controlling Electron Spin Decoherence in Nd-based Complexes via Symmetry Selection.

Jing Li,Yi-Quan Zhang,Zhong-Wen Ouyang,Lei Yin,Zheng-Cai Xia,Fei Yu,Shi-Jie Xiong,Xing-Long Wu,Johan Van Tol,You Song,Zhenxing Wang

doi:10.1016/j.isci.2020.100926

Abstract

SummaryLong decoherence time is a key consideration for molecular magnets in the application of the quantum computation. Although previous studies have shown that the local symmetry of spin carriers plays a crucial part in the spin-lattice relaxation process, its role in the spin decoherence is still unclear. Herein, two nine-coordinated capped square antiprism neodymium moieties [Nd(CO3)4H2O]5– with slightly different local symmetries, C1 versus C4 (1 and 2), are reported, which feature in the easy-plane magnetic anisotropy as shown by the high-frequency electron paramagnetic resonance (HF-EPR) studies. Detailed analysis of the relaxation time suggests that the phonon bottleneck effect is essential to the magnetic relaxation in the crystalline samples of 1 and 2. The 240 GHz Pulsed EPR studies show that the higher symmetry results in longer decoherence times, which is supported by the first principle calculations.

Highlights

Single-molecule magnets (SMMs) (Sessoli et al, 1993) are promising candidates as the quantum bits, the basic building blocks of a quantum computer according to Leuenberger and Loss’s proposal (Leuenberger and Loss, 2001), in which they show slow spin relaxation behaviors between the bistable ground states with an energy barrier
Our work indicates that the higher symmetry results in the longer decoherence times, which is explained by the first principle calculations
In summary, typical magnetic relaxation behaviors have been observed for two mononuclear Nd(III) complexes 1 and 2 with strong easy-plane magnetic anisotropy due to the strong phonon bottleneck effect

Summary

INTRODUCTION

Single-molecule magnets (SMMs) (Sessoli et al, 1993) are promising candidates as the quantum bits (qubits), the basic building blocks of a quantum computer according to Leuenberger and Loss’s proposal (Leuenberger and Loss, 2001), in which they show slow spin relaxation behaviors between the bistable ground states with an energy barrier. The strong decoherence must be overcome to implement the envisaged application Specific design criteria, such as nuclear-spin-free ligands (Yu et al, 2016), clock transitions (Zadrozny et al, 2017; Shiddiq et al, 2016), and low-energy vibrations (Atzori et al, 2017) have been developed to improve the quantum coherence time and temperature. We report two capped square antiprism neodymium complexes, [C(NH2)3]5[Nd(CO3)4H2O]∙2H2O (1) and [C(NH2)3]4[H3O][Nd(CO3)4H2O]∙9.5H2O (2), which have different local symmetries, C1 (1) versus C4 (2), in the neodymium moieties [Nd(CO3)4H2O]5– Both neodymium-based complexes are easy-plane magnetic anisotropic and show field-induced slow magnetic relaxation behaviors, which is rare in lanthanide complexes. Our work indicates that the higher symmetry results in the longer decoherence times, which is explained by the first principle calculations

RESULTS AND DISCUSSIONS

CONCLUSIONS

Transparent Methods