Phase transformation B1 to B2 in TiC, TiN, ZrC and ZrN under pressure

• Дата: 2013
• Автори: Ivashchenko, V.I., Turchi, P.E.A., Shevchenko, V.I.
• Формат: Стаття
• Мова: English
• Опубліковано: Інститут фізики конденсованих систем НАН України 2013
• Назва видання: Condensed Matter Physics
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/120835
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Phase transformation B1 to B2 in TiC, TiN, ZrC and ZrN under pressure / V.I. Ivashchenko, P.E.A. Turchi, V.I. Shevchenko // Condensed Matter Physics. — 2013. — Т. 16, № 3. — С. 33602:1-9. — Бібліогр.: 32 назв. — англ.

Phase stability of various phases of MX (M=Ti, Zr; X=C, N) at equilibrium and under pressure is examined based on first-principles calculations of the electronic and phonon structures. The results reveal that all B1 (NaCl-type) MX structures undergo a phase transition to the B2-structures under high pressure in agreement with the previous total-energy calculations. The B1-MX structures are dynamically stable under very high pressure (210-570 GPa). The pressure-induced B2 (CsCl-type) MC phases are dynamically unstable even at high pressures, and TiN and ZrN are found to crystallize with the B2-structure only at pressures above 55 GPa. The first-order B1-to-B2 phase transition in these nitrides is not related to the softening of phonon modes, and the dynamical instability of B2-MX is associated with a high density of states at the Fermi level.