A new form of Ca3P2 with a ring of Dirac nodes

• DOI: 10.1063/1.4926545
• Publication Date: 2015-07-09T18:51:40Z
• Authors: Lilia S. Xie; Leslie M. Schoop; Elizabeth M. Seibel; Quinn D. Gibson; Weiwei Xie; Robert J. Cava
• Keywords: Rietveld Refinement

We report the synthesis and crystal structure of a new high-temperature form Ca3P2. The was determined through Rietveld refinements synchrotron powder x-ray diffraction data. This Ca3P2 has hexagonal Mn5Si3 type, with Ca ion deficiency compared to ideal 5:3 stoichiometry. yields stable, charge-balanced compound Ca2+ P3−. also observation secondary hydride phase, Ca5P3H, which again is compound. calculated band indicates that it three-dimensional Dirac semimetal highly unusual ring nodes at Fermi level. states are protected against gap opening by mirror plane in manner analogous what seen for graphene.