Determining the high-pressure phase transition in highly-ordered pyrolitic graphite with time-dependent electrical resistance measurements

作者：Montgomery Jeffrey M; Kiefer Boris; Lee Kanani K M^*

来源：Journal of Applied Physics, 2011, 110(4): 043725.

DOI：10.1063/1.3627372

Long-duration, high-pressure resistance measurements on highly-ordered pyrolytic graphite in a diamond-anvil cell show a sluggish phase transition occurring at similar to 19 GPa, as evidenced by the time-dependent behavior of the sample resistance. The instantaneous resistance response to pressure adjustment shows a similar to 10 GPa hysteresis that has been observed previously, rendering the conjectured direct relationship between resistance and phase-transition tentative. In contrast, the evolution of the resistance with time after the instantaneous response shows a systematic, reproducible, and distinct behavior, which allows reducing the uncertainty in transition pressure to similar to 2 GPa. This largely reduced hysteresis shows explicitly that the phase transition is directly related to changes in electronic structure and resistance and establishes consistency with other commonly used experimental techniques to explore phase transitions at high pressures. We augment our experiments with first-principle density-functional theory computations to evaluate the pressure dependence of the electronic density of states of proposed candidate structures for the post-graphite phase.

• 出版日期2011-8-15