The structure of sc16 GaP obtained at 17.5 GPa and 1400 K

ABSTRACT

Using a laser-heated diamond anvil cell, a powdered sample of gallium phosphide was compressed to 17.5 GPa and heated up to 1400 K. The material obtained was characterized at room temperature using synchrotron x-ray diffraction. Experimental results were compared with first-principles calculations. The polymorph observed assumes the simple cubic structure (sc16) initially reported for GaAs at high pressures. Microdiffraction mapping showed variable grain sizes of the synthesized phase, with the largest grains located in the middle of the heated spot. Structural refinements were performed on selected grains. The structure predicted based on first-principles calculations is in close agreement with the experiments. The two Ga–P bonds show similar lengths in sc16-GaP; however, the bond angles differ, resulting in a distorted tetrahedral coordination geometry.

KEYWORDS:

• Gallium phosphide
• high-pressure
• semiconductor
• phase transition

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was partially supported by COMPRES, the Consortium for Materials Properties Research in Earth Sciences under National Science Foundation (NSF) Cooperative Agreement EAR 1606856. AM acknowledges financial support through Projects MAT2016-75586-C4-3-P (MINECO, Spain) and PID2019-106383GB-C43 (MICINN, Spain). The MALTA Consolider Team Research Network is supported by Project RED2018-102612-T (MICIU, Spain). The experimental work was conducted at High Pressure Collaborative Access Team (HP-CAT), Sector 16, Advanced Photon Source (APS), Argonne National Laboratory. HPCAT operations are supported by DOE-NNSA's Office of Experimental Sciences. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Use of the COMPRES-GSECARS gas loading system was supported by COMPRES, the Consortium for Materials Properties Research in Earth Sciences under National Science Foundation (NSF) Cooperative Agreement EAR 1606856 and by GSECARS through (NSF) grant EAR-1634415 and DOE grant DE-FG02-94ER14466. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy (DOE), National Nuclear Security Administration under Contract DE-AC52-07NA27344.