We acknowledge beam time awarded by J-PARC (proposals 2018AU1401 and 2018B0014), SPring-8 (proposals 2018B1095 and 2018A2061) and from ANSTO. B.L., Zhao Zhang, Zhe Zhang, W.R. and Zhidong Zhang were supported by the Hundred Talents Project of CAS and the National Natural Science Foundation of China (grants 11804346, 51671192 and 51531008). T.S. was supported by JSPS KAKENHI (grant number JP18K05032). S.L. and J.W. acknowledge financial support from the US National Science Foundation (grant number CBET-1708968) and the Florida State University through the Energy and Materials Initiative. H.W. acknowledges support from the National Natural Science Foundation of China (grant number 11874429) and the High-Level Talents Project of Hunan Province (grant number 2018RS3021). We also thank W. Zhang, A. Chen and H. Zeng of Setaram for testing the sample using a μDSC 7 EVO.

Reviewer information

Nature thanks Thomas Brueckel, Claudio Cazorla and the other anonymous reviewer(s) for their contribution to the peer review of this work.