Unformatted text preview: mixes substitutionally with copper, its main eﬀect being to increase the electron concentration. (a) Assume that the zinc-copper alloy will undergo a phase transition to bcc as soon as the Fermi sphere ﬁrst touches some point of the edge of the Brillouin zone. Show that this transition occurs on the order of 36% zinc concentration. Remember that in a fcc conventional unit cell there are four ions. You should assume that the free electron approximation is valid. (b) As the concentration of zinc further increases, another phase transition occurs when the Fermi surface intersects the Brillouin zone of the bcc lattice. What is this second concentration of zinc? (c) Why do these transitions occur? ============================= For students of 621 only: Q 5: Kittel 9.8...
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- Fall '07
- Physics, Condensed matter physics, Brillouin zone, N.P. Armitage Grader, Paula Mellado Fall, Graders mail box