Condensed Matter Experiments

Course content

This course provides an introduction to selected techniques used in experimental condensed matter physics, with a focus on low-temperature physics, cryogenic techniques, and electron transport phenomena at low temperatures. The intention is to prepare the student for graduate level course work and experimental research in the fields of low-temperature solid state physics, quantum transport, and the characterization of semiconducting and superconducting quantum devices. The students will learn key concepts that are essential in these fields and, more generally, have advanced our understanding of the interplay between properties of materials on the mesoscopic scale and the quantum engineering of advanced functional electronic devices.

Topics: Quantum and cryoliguids. Thermal properties of matter at low temperatures. Cooling methods, heat transfer at cryogenic temperatures, and the physics of thermometry. Operating principles of a modern cryostat (3He/4He dilution refrigerator). Basic concepts of current and heat flow at low temperatures, and resistance of metals and semiconductors. Brief introduction to the fabrication of crystals, heterostructures, and nanostructures. Methods of measuring accurately electrical properties of a mesoscopic sample, including conductance and noise. Interplay of important (scattering) length scales and device dimenionality (3D, 2D, 1D, 0D). Field-effect in semiconducting structures, basic transport properties of devices made from superconducting materials. Conductance quantization in quasi-2D electron gases. Coulomb blockade in metallic single-electron transistors, quantum dots, and artificial atoms.

The course will be a combination of lectures, exercises, discussions of experimental breakthroughs from literature. In parallel, and not necessarily connected to the lectures, a selection of mandatory laboratory experiments performed off hours in small groups. The student is expected to actively take part in all activities, and gain a background for pursuing experimental work in local groups dedicated to the physics of low-temperatures and solid-state quantum devices.

Education

MSc Programme in Physics
MSc Programme in Physics with a minor subject

Learning outcome

Skills:

After the course the student is expected to have the following skills:

  • After the course the student is expected to have the following skills:

  • Describe the properties of gaseous and liquid helium and nitrogen, and differentiate between 3He and 4He at low temperatures.
  • Identify the main components of a cryostat, and explain physical properties of solids that are relevant for the conduction and isolation of heat.
  • Explain the temperature dependence of electron-phonon coupling, and its implications for achieving low electron temperatures in quantum devices.
  • Describe primary and secondary thermometers, and give examples.
  • Describe different ways of measuring cryogenic electron and phonon temperatures.
  • Explain resistivity, resistance, conductivity, conductance.
  • Explain the concept of a semiconducting heterostructure, and the role of doping.
  • Explain two- and four-terminal measurements,
  • Explain basic concepts of electrical noise and lock-in detection
  • Explain concepts of high-frequency techniques, including radio-frequency reflectometry.
  • Explain the concept of coherence, and how it relates to particles and waves.
  • Explain typical scales for coherence and scattering associated with electrons and phonons.
  • Work in small teams and efficiently perform an experiment, analyze the data and find a convincing interpretation. Communicate the results in a written document that places the findings into the context of what was known or expected before the experiment, and how they inform other experiments or raise important questions.

Knowledge:

After the course the student will be familiar with physical concepts that address the behavior of solids at low temperature, the flow of heat and electrical carriers, and the role of material boundaries and dimensionality. The student will know how interactions can be described by elastic and inelastic scattering, and the important role of coherence and interference. Most importantly, the student will understand how these theoretical concepts connect to key experimental methods used in the daily life of experimental groups dedicated to solid state quantum devices. Discussions of hot-off-the-press experimental literature and/or hands-on experiments in the course laboratory will prepare the young scientist for a smooth transition into an experimental research group.

Competences:

This course will provide the students with a background for further studies specializing in the physics and applications of low-temperature techniques and solid-state quantum devices. The students will gain insight into the real-life execution of scientific experiments and the teamwork and software tools necessary to analyze and report results, in preparation for pursuing for example an experimental M.Sc. or PhD project.

Lectures, problem sets, group work, selected scientific articles and/or hands-on experiments.

will be announced in Absalon

Familiarity with quantum mechanics, condensed matter physics, statistical physics.
Academic qualifications equivalent to a BSc degree is recommended. Basic knowledge in superconductivity is useful.

ECTS
7,5 ECTS
Type of assessment
Oral examination, 20 minutes
Oral examination without time for preparation, covers content of course and written reports.
Aid
All aids allowed
Marking scale
7-point grading scale
Censorship form
No external censorship
Several internal examiners.
Criteria for exam assessment

see learning outcome

Single subject courses (day)

  • Category
  • Hours
  • Lectures
  • 30
  • Preparation
  • 145,5
  • Exercises
  • 30
  • Exam
  • 0,5
  • English
  • 206,0