Stability of the Bulk Phase of Layered ZnO
Abstract
Recently a novel phase of ZnO has been synthesized which is analogous to α-boron nitride, although more three dimensional, and consists of planar hexagonal sheets of ZnO. Examining the dynamic stability of the structure, we find unstable phonon modes over a considerable part of the Brillouin zone. Local-density approximation (LDA) and generalized gradient approximation level calculations have usually been able to predict the structural stability of s-p bonded systems. The failure in the present case is a surprise and is traced to the self-interaction error which incorrectly locates the localized Zn d states in the valence band of ZnO. Correcting for this with a Hubbard-like U on the Zn d states, the optimized structure is predicted to be stable. This highlights the fact that the large bond length contraction that one finds in going from sp3- to sp2-type bonding results in an increased necessity to correct for self-interaction errors.
- Publication:
-
Physical Review Letters
- Pub Date:
- August 2011
- DOI:
- 10.1103/PhysRevLett.107.085508
- Bibcode:
- 2011PhRvL.107h5508R
- Keywords:
-
- 61.66.-f;
- 63.20.-e;
- 71.20.-b;
- Structure of specific crystalline solids;
- Phonons in crystal lattices;
- Electron density of states and band structure of crystalline solids