So..DEFINATELY (probably) hcpÖbutÖwhen does bcc become stable?

• From the phonon frequencies, we know that bcc is unstable at 0 K and high P.

• From the free energies and analysis of atomic positions, we know that bcc is mechanically (if not thermodynamically) stable at high pressures and temperatures.

• What happens to the system as we lower T?

  • Stresses on the box
  • Atomic deviation from bcc structure

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