A new form of Ca3P2 with a ring of Dirac nodes

By Lilia S. Xie, L. Schoop, E. Seibel, Q. Gibson, W. Xie, R. Cava. 2015

177 citations recorded by the source corpus.

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

Subfields: Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/7b2b5fa326b958817911289d3ed96ca4faff4eaa

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

1. Ashvin Vishwanath
2. Zhong Wang
3. N. P. Armitage
4. E. Mele
5. Shoucheng Zhang
6. Ling Lu
7. Zhongbo Yan
8. Ren Bi

In Electronic, Optical and Magnetic Materials

1. Ling Lu
2. Ashvin Vishwanath
3. N. P. Armitage
4. E. Mele
5. Shoucheng Zhang

In Materials Chemistry

1. Ashvin Vishwanath
2. Zhong Wang
3. Shoucheng Zhang
4. N. P. Armitage
5. Ling Lu
6. E. Mele
7. Zhongbo Yan
8. Ren Bi

Citations in the corpus

• Nodal-link semimetals (2017, background): “Nodal rings have been predicted (e.g., Cu3PdN[60, 61],Hg3As2[74], Ca3P2[63, 75], 3D carbon networks[58], CaP3[76], Alkali Earth Metals[77, 78]) and experimentally studied in quite a few materials (e.g., PbTaSe2[62], ZrSiTe[79], ZrSiS[80–84]).”
• Nodal-knot semimetals (2017, background): “There are quite a few material candidates of nodal lines: Cu3NPd and Cu3NZn[39, 40], calcium phosphide[52, 53], carbon networks[37], CaP3[54], alkali earth materials[55, 56], to name a few.”
• Weyl and Dirac semimetals in three-dimensional solids (2017, background): “Other proposals include a new form of Ca3P2 (Xie et al., 2015).”