Experimental and theoretical equation of state of cubic boron nitride

Elise Knittle, Renata M. Wentzcovitch, Raymond Jeanloz, Marvin L. Cohen

Research output: Contribution to journalArticlepeer-review

287 Scopus citations


The phase diagram of boron nitride (BN) is similar to that of carbon, incorporating phases at high temperatures and pressures whose structures and physical properties resemble diamond. Cubic zinc-blende-structured BN is especially important because it is extremely hard-second only to diamond. Here we report the first measurement of the 300-K equation of state of this material to ultrahigh pressures (115 GPa), and obtain a zero-pressure bulk modulus of 369 ± 14 GPa. A theoretical equation of state derived from first-principles pseudopotential calculations yields a 300-K isotherm that agrees with our experimental results to better than 2.5% in volume and 2.0% in bulk modulus. The high-pressure Hugoniot (shock-wave equation of state) calculated from our equation of state for BN is in good agreement with existing shock-wave data. Our study illustrates the reliability of current experimental techniques (such as the ruby-fluorescence calibra-tion) and theoretical methods (pseudopotentials) for characterizing the behaviour of superhard, incompressible materials under high pressure.

Original languageEnglish (US)
Pages (from-to)349-352
Number of pages4
Issue number6205
StatePublished - 1989


Dive into the research topics of 'Experimental and theoretical equation of state of cubic boron nitride'. Together they form a unique fingerprint.

Cite this