This module is aimed at final year level 8 physics students. Firstly it further develops the students’ knowledge of the structure of solids. It provides an introduction to the underlying theory of energy transport and electron behaviour in solids. The student is introduced to the historical development of lattice energetics models and the electronic band structure based on the quantum mechanical model of the solid. The module shows how the quantum model can be successfully applied to the technologically important properties such as electrical conductivity and optical absorption and emission in the solid. Advanced models of the band structure are introduced and the specific properties of semiconductors such as Si and GaAs are covered in detail, with descriptions of direct and indirect bandgaps and excitonic effects. Various methods of band engineering are discussed leading to the formation and description of artificial systems. Dielectric properties of materials are discussed. The principle of superconductivity is introduced along with the concept of electron correlation.
- Crystal systems review;Quasicrystals;
- Plastics and Polymers – Structure, production,physical properties, Conducting Polymers
- Ceramic Systems – Structure, production,physical properties. Naturally occurring and manmade systems such as Zirconia and Sialon systems.
- Lattice Dynamics: propagation of sound, quantum oscillator & vibrational states; Einstein model, Debye model, Dulong Petit limit, vibrations of periodic systems, one dimenstional systems, acoustic and optical modes, three dimensional systems; Phonons and quantisation
- The concept of a metal reviewed Drude model, Sommerfeld model, successes and failures; Electrons in a periodic lattice, the independent electron approximation, density of k, E states, the band structure; Limiting electron freedom, Born-van Karman boundary conditions, the Bloch theorem; Nearly free models, the Brillouin approach; Fermi surfaces; Band properties, effective mass, motion of electrons, electrical conductivity, mechanisms, scattering mechanisms, thermal effects, radiative transitions, mapping the band structure;the band strucutre of GaAs and Si compared; The tight-binding model; Bands arising from a single electronic level; Group IA and IIA elements, Group IV elements, Transition metals; Tight-binding and nearly-free comparison
- Semiconductors, Thermal populations, intrinsic and extrinsic, Impurity states and doping; Light holes, heavy holes and excitons; The band structure of GaAs and Si revisitied;III-V and II-VI structures;Hall effect; Magnetoresistance; Quantum Hall Effect
- Band engineering, Artificial structures, layers quantum wells and heterostructures. Quantum dots. Bandstructure engineering using organic moleules
- Dielectric Properties of Solids- Origin of dielectric properties, AC permittivity, Loss factors, Polarisation, Mechanisms of polarisation and polarisability, Frequency response of polarisation, Classification of dielectrics, Piezoelectricity and electrostriction, Pyroelectricity and ferroelectricity, Applications for dielectric materials.
- Superconductivity, Meissner effect, flux quantisation, descriptive BCS theory, Cooper pairs, Josephson tunneling, quantum interference (SQUID); Superconductiving materials
A combination of techniques will be employed as appropriate to each element of the module content including lectures, discussion, problem-solving sessions, self learning.
Laboratory based experiments aligned to module content.
| Module Content & Assessment | |
|---|---|
| Assessment Breakdown | % |
| Formal Examination | 40 |
| Other Assessment(s) | 60 |