Mechanochemical Synthesis of Semiconducting Diamonds

We predict a mechanochemical synthetic route to obtain semiconducting diamonds through rapid uniaxial compression of graphite. Ensembles of quantum molecular dynamics simulations reveal that a subset of products formed from initially perfect graphite crystals exhibit significant disorder and partial band gap closure. Seeding atomic vacancies in graphite is shown to significantly bias toward forming semiconducting products. We identify a strong correlation between gap closure and disordered configurations that informs which kinds of structural defects are associated with formation of the semiconducting material. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.