CondMat07PS1

# CondMat07PS1 - CONDENSED MATTER PHYSICS 171.405 / 171.621...

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CONDENSED MATTER PHYSICS 171.405 / 171.621 Instructor: N.P. Armitage Grader: Paula Mellado Fall 2007 Problem Set # 1 Due to Grader’s mail box by Oct 1st ============================= Q #1: Kittel Problem 1.3 ============================= Q #2: Cobalt exists in two crystal structures: a-Co which is hcp with a = 0.25 nm and c = 0.41 nm, and b-Co which is fcc with a cubic lattice spacing of 0.35 nm. What is the density difference between the two phases? ============================= Q #3: The fcc is the most dense and the sc is the least dense of the three cubic Bravais lattices. The diamond structure is even less dense than these. Once measure of this is coordination number: fcc, 12; bcc, 8; sc, 6; diamond, 4. Another is by an analysis of their “packing fraction”, which is defined as the ratio of space filled to total space when spheres are assigned to lattice points and their radii chosen so that identical spheres on neighboring points just touch. Give the packing fraction for these 4 crystal
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## This note was uploaded on 12/06/2009 for the course PHYSICS 171.405 taught by Professor N.peterarmitage during the Fall '07 term at Johns Hopkins.

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