C8519 - CONDENSED MATTER PHYSICS 2

Learning outcomes

By the end of the course, the students will learn electronic transport phenomena and optical properties in condensed matter. They will be able to apply theoretical models to the evaluation and prediction of electronic charge transport parameters, and to compare the predictions with experimental observations. They will be able to apply the models to obtain predictions of radiation- matter interaction phenomena and to understand the relevant technological and scientific applications.

Course contents

Electronic Transport in Crystals
Models for the prediction of electronic transport in crystalline solids. Definition and mode of key quantities characterizing electronic transport—such as current density, electrical conductivity, and carrier mobility—ranging from classical to semiclassical approximations. Analysis of non-interacting electrons in perfect crystals, including the effects of electron-electron interactions and scattering mechanisms.

The theoretical models covered include:

• Drude model
• Sommerfeld model
• Transport of non-interacting Bloch electrons
• Semiclassical theory of electronic transport
• Effective mass approximation
• Relaxation time approximation
• Boltzmann transport equation
• Discussion of coupled thermal, electrical, and magnetic phenomena, including Seebeck and Peltier effects, and magnetoresistance.
• Treatment of electron-electron interactions within Hartree and Hartree-Fock approximations.
• Overview of scattering mechanisms and Matthiessen’s rule.

2. Optical Properties of Solids

Introduction to the fundamental phenomenological models describing the optical properties of solids, with a focus on their connection to electronic transport.

The topics include:

Optical functions and their relationship to transport phenomena

• Maxwell’s equations in condensed matter
• Kramers-Kronig relations

Optical properties of semiconductors:

• Measurement of cyclotron frequency to determine the effective mass
• Absorption spectra, both above and below the band gap
• Electronic transitions

Optical properties of insulators:

• Dielectric response and polarization effects
• Optical effective mass
• Polarons and polaritons
• Color centers

Optical properties of metals:

• Plasma frequency
• Bulk and surface plasmons

Applications of light-matter interaction:

• Experimental techniques including Raman and Brillouin spectroscopy

3. Impurities, Defects, and Disorder in Solids

Analysis of point and extended defects and their effects on material properties. Surface phenomena.

• Surface states

• Definition and measurement of the work function

• Surface-sensitive experimental techniques

• Influence of structural disorder on transport properties, including the Mott metal-insulator transition and the appearance of Urbach tails in optical spectra.

Readings/Bibliography

Neil W. Ashcroft and N. David Mermin, Solid State Physics, Harcourt College Publisher

M Marder, Condensed matter physics, Wiley

M. S. Dresselhaus SOLID STATE PHYSICS PART II, Optical Properties of Solids, on web.mit.edu

The lecture notes will be made available on the web site:

Virtuale (unibo.it) [https://virtuale.unibo.it/]

 

 

Teaching methods

Lectures. Group discussion on selected topics.

Exercises. Discussion on selected applications.

Assessment methods

Oral exam.

The final oral exam is designed to assess the achievement of the course learning objectives. The student is expected to clearly present and discuss the fundamental aspects of electronic transport and optical properties in condensed matter.

The examination will begin with a question on a topic chosen by the student, followed by a second question selected by the examiner.

The final evaluation and grade will reflect the student’s ability to critically analyze and articulate the key concepts covered in the course.

Teaching tools

Slide presentations and review articles will be made available via Virtuale (unibo.it) [https://virtuale.unibo.it/]

Office hours

See the website of Daniela Cavalcoli