Phase Transition of Graphitic-C₃N₄ under High Pressure by In Situ Resistance Measurement in a Diamond Anvil Cell

In situ resistance measurement of Graphitic-C₃N₄ has been performed under high pressure in a diamond anvil cell. The result reveals that there are changes of electron transport behaviour. As the pressure increases from ambient to 30GPa, three abnormal resistance changes can be found at room temperature and two are found at 77K. The abnormal resistance dropped at 5GPa is close to the phase transition pressure from the P6m2 structure to the p structure predicted by Lowther et al. Phys. Rev. B 59 (1999) 11683 Another abnormal change of resistance at 12GPa is related to the phase transition from g-C₃N₄ to cubic-C₃N₄ Teter and Hemley, Science 271 (1996) 53.