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PHYS3004 Crystalline Solids. Prof. P.A.J. de Groot. 1. BONDING IN SOLIDS. Born-Oppenheimer Approximation Linear Combination of Atomic Orbitals. 1. BONDING IN SOLIDS. Covalent bonding Ionic bonding Metallic bonding Van der Waals bonding. 1. BONDING IN SOLIDS. Covalent bonding: LCAO
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PHYS3004Crystalline Solids Prof. P.A.J. de Groot
1. BONDING IN SOLIDS • Born-Oppenheimer Approximation • Linear Combination of Atomic Orbitals
1. BONDING IN SOLIDS • Covalent bonding • Ionic bonding • Metallic bonding • Van der Waals bonding
1. BONDING IN SOLIDS • Covalent bonding: LCAO • Bonding and anti-bonding states
R1 2. CRYSTAL LATTICES • Lattice & basis • Wigner-Seitz cell
3. RECIPROCAL LATTICE • Diffraction of waves (x-rays) • Reciprocal lattice
3. RECIPROCAL LATTICE • First Brillouin zone • Bloch theorem:
4. FREE ELECTRON MODEL – JELLIUM • Electrons in a box • Time independent Schrödinger eq. • Plane wave solutions • Boundary conditions (box is finite)
4. FREE ELECTRON MODEL – JELLIUM • Density of states • Fermi energy
4. FREE ELECTRON MODEL – JELLIUM • Charge oscillations – plasmons • Electrical transport (relaxation time) • Quantum Jellium • Hall effect • Breakdown of Jellium Model
5. NEARLY-FREE ELECTRON MODEL Perturbation theory – only significant changes in E(k) near degenerate points
5. NEARLY-FREE ELECTRON MODEL • Effective mass • Electrons and holes
6. TIGHT BINDING jelliumnearly-free electrons tight bindingatoms
6. TIGHT BINDING • LCAO • Bloch theorem • Crystal momentum
7. MAGNETIC PROPERTIES OF CRYSTALS • Paramagnetism – partly filled shells • Curie’s law
7. MAGNETIC PROPERTIES OF CRYSTALS • Pauli paramagnetism • Ferromagnetism & mean field theory
8. SEMICONDUCTORS • Intrinsic • Doping (donors/acceptors) Valence band Conduction band
8. SEMICONDUCTORS • Transport (electrons/holes) • Einstein relation
Vs metal SiO2 p-Si x 8. SEMICONDUCTORS • MOSFET • Depletion width • Gate-controlled conduction channel • 2D electron gas – quantum Hall effect