Dimerization in the III-V semiconductor gallium phosphide
ORAL
Abstract
We explored the high-pressure polymorphism of GaP using microdiffraction and first principles techniques. After laser heating at ~40 GPa and 1300 K we found that GaP assumes the super-Cmcm structure featuring the formation of short P-P dimers. A comparison of total energy and enthalpy suggests that the phase here proposed is more stable than earlier considered arrangements at 0K, it is therefore the best candidate high-pressure polymorph of GaP in the range ~ 20-40 GPa. The symmetry lowering is explained by the mixed nature of the bonding in the new phase.
While the polymorphism of III-V semiconductors has been considered a settled problem for more than a decade, our results show that this is not the case for all semiconductors, and, more importantly, that the metallization of GaP is associated with the formation of a range of bond types and coordination geometries in contrast with earlier consensus.
While the polymorphism of III-V semiconductors has been considered a settled problem for more than a decade, our results show that this is not the case for all semiconductors, and, more importantly, that the metallization of GaP is associated with the formation of a range of bond types and coordination geometries in contrast with earlier consensus.
*This research was sponsored by the NNSA under the SSAP through DOE Cooperative Agreement #DE-NA0001982. This work was performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344. SNL is managed and operated by NTESS for U.S. DOE/NNSA under contract DE-NA0003525.
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Presenters
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Barbara Lavina
- University of Nevada, Las Vegas
- Physics and Astronomy, University of Nevada, Las Vegas