Chin. Phys. Lett.  2021, Vol. 38 Issue (3): 030303    DOI: 10.1088/0256-307X/38/3/030303
 GENERAL |
Experimental Protection of the Spin Coherence of a Molecular Qubit Exceeding a Millisecond
Yingqiu Dai1,2,3†, Yue Fu1,2,3†, Zhifu Shi1,2,3, Xi Qin1,2,3, Shiwei Mu1,2,3, Yang Wu1,2,3, Ji-Hu Su1,2,3, Yi-Fei Deng4, Lei Qin4, Yuan-Qi Zhai4, Yan-Zhen Zheng4, Xing Rong1,2,3*, and Jiangfeng Du1,2,3*
1Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
2CAS Key Laboratory of Microscale Magnetic Resonance, University of Science and Technology of China, Hefei 230026, China
3Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
4Frontier Institute of Science and Technology (FIST), Xi'an Jiaotong University, Xi'an 710054, China
 Abstract Molecular qubits are promising as they can benefit from tailoring and versatile design of chemistry. It is essential to reduce the decoherence of molecular qubits caused by their interactions with the environment. Herein the dynamical decoupling (DD) technique is utilized to combat such decoherence. The coherence time for a transition-metal complex {(PPh$_4$)}$_2$[Cu(mnt)$_2$] is prolonged from 6.8 µs to 1.4 ms. The ratio of the coherence time and the length of $\pi$/2 pulse, defined as the single qubit figure of merit ($Q_{\rm M}$), reaches $1.4 \times 10^5$, which is 40 times greater than what previously reported for this molecule. Our results show that molecular qubits, with milliseconds coherence time, are promising candidates for quantum information processing. Received: 31 December 2020      Published: 06 February 2021 Fund: Supported by the National Key R&D Program of China (Grant Nos. 2018YFA0306600 and 2016YFB0501603), the Chinese Academy of Sciences (Grant Nos. GJJSTD20170001, QYZDY-SSW-SLH004, and QYZDB-SSW-SLH005), and Anhui Initiative in Quantum Information Technologies (Grant No. AHY050000). X.R. thanks the Youth Innovation Promotion Association of Chinese Academy of Sciences for their support. Y.Z.Z. thanks the support from Wuhan National High Magnetic Field Center (Grant No. 2015KF06).