Reduced Local Symmetry in Lithium Compound Li2SrSiO4 Distinguished by an Eu3+ Spectroscopy Probe.

Research on lithium compounds has attracted much attention nowadays. However, to elucidate the precise structure of lithium compounds is a challenge, especially when considering the small ions that may be transferred between the interstitial voids. Here, the discovery of reduced local symmetry (symmetry breaking) in small domains of Li2SrSiO4 is reported by employing Eu3+ as a spectroscopic probe, for which X-ray, neutron, and electron diffraction have confirmed the average long-range structure with the space group P3121. However, luminescence shows a lower local symmetry, as confirmed by the extended X-ray absorption fine structure. By considering the reduced symmetry of the local structure, this work opens the door to a new class of understanding of the properties of materials.