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Graduate Lecture Series 29 June – 3 July, 2009 Prof Ngee-Pong Chang. Lecture 2 Fermi Gas. Enrico Fermi 1901 - 1954. Paul Dirac 1902 - 1984. Band Theory of Metals. Start with isolated Sodium Atom. Ionisation Energy of Sodium 5.14 eV. Band Theory of Metals.
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Graduate Lecture Series 29 June – 3 July, 2009 Prof Ngee-Pong Chang Lecture 2 Fermi Gas
Enrico Fermi 1901 - 1954 Paul Dirac 1902 - 1984
Band Theory of Metals Start with isolated Sodium Atom Ionisation Energy of Sodium 5.14 eV
Band Theory of Metals Ionisation Energy of Sodium 5.14 eV
Band Theory of Metals Bring two Sodium Atoms together Splitting of 3s level with 2 Sodium atoms
Band Theory of Metals Bring six Sodium Atoms together Splitting of 3s level with 6 Sodium atoms
Band Theory of Metals Splitting of 3s levels with Sodium atoms in crystalline solid
Fermi-Dirac Distribution electrons holes
Probability of Occupancy T=0 T > 0 1.0 0.0
² F Filling up the Fermi Sea In One Dimensional Box 30 Energy in units 20 10
1-Dimensional Fermi Gas Sum Over Spins
1-Dimensional Fermi Gas Single Spin Orientation Fermi Surface dependence on number of electrons
2-Dimensional Fermi Gas Single Spin Orientation Fermi Surface dependence on number of electrons
3-Dimensional Fermi Gas Single Spin Orientation Fermi Surface dependence on number of electrons
1-Dimensional Fermi Gas Single Spin Orientation Total Energy
2-Dimensional Fermi Gas Single Spin Orientation Total Energy
3-Dimensional Fermi Gas Single Spin Orientation Total Energy
http://upload.wikimedia.org/wikipedia/en/c/c5/DOS_multdim.jpghttp://upload.wikimedia.org/wikipedia/en/c/c5/DOS_multdim.jpg
3-Dimensional Fermi Gas Density of States
2-Dimensional Fermi Gas Density of States
1-Dimensional Fermi Gas Density of States
Conduction Band Valence Band
http://boulder.research.yale.edu/Boulder-2005/Lectures/Matveev/Boulder%20lecture.pdfhttp://boulder.research.yale.edu/Boulder-2005/Lectures/Matveev/Boulder%20lecture.pdf
A graphene nanoribbon field-effect transistor (GNRFET). Here contacts A and B are at two different Fermi levels EF1 and . EF2
Landauer formula i t t’ i’ 1927 - 1999 Conductance
µ Gas Pressure on the Wall A cos θ v δ t θ A
Pressure due to Non-Relativistic Degenerate Fermi Gas Equation of state for Fermi Gas since at T = 0 We have for a metal