Softening of ultra-incompressible CrN at high pressure

ORAL

Abstract

We report a dramatic softening of CrN above 1.5 GPa, (the bulk modulus decreasing from K$_{0}$=413(20) GPa to 243(10) GPa) associated to a structural transition. From the structural and magnetic data under pressure, and ab-initio calculations we suggest that this effect is purely electronic, driven by the proximity of the ionic Cr-Cr bond to itinerant electron limit. Our results help to understand fundamental aspects of the chemical bond that gives superhard materials their superior al properties, and could be useful to preserve the mechanical properties of CrN.

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Authors

  • Francisco Rivadulla

    Physical Chemistry Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain, Physical Chemistry Department, University of Santiago de Compostela, 15782-Santiago de Compostela, Spain

  • Manuel Banobre

    Physical Chemistry Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain

  • Alberto Pineiro

    Applied Physics Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain

  • Victor Pardo

    Applied Physics Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain

  • Daniel Baldomir

    Applied Physics Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain

  • Arturo Lopez-Quintela

    Physical Chemistry Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain

  • Jose Rivas

    Applied Physics Department, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain, Applied Physics Department, University of Santiago de Compostela, 15782-Santiago de Compostela, Spain