Semiconductor Quantum Electronics
This module handbook serves to describe contents, learning outcome, methods and examination type as well as linking to current dates for courses and module examination in the respective sections.
PH2290 is a semester module in English or German language at Master’s level which is offered in summer semester.
This module description is valid from SS 2020 .
If not stated otherwise for export to a non-physics program the student workload is given in the following table.
|Total workload||Contact hours||Credits (ECTS)|
|150 h||30 h||5 CP|
Responsible coordinator of the module PH2290 is Martin Brandt.
Content, Learning Outcome and Preconditions
Semiconductor-based quantum electronic devices and circuits play a pivotal role in the current development of processors for quantum computing, in particular since they can be integrated with the highly versatile existing microelectronics. Furthermore, these devices are fabricated using with the identical technology. The aim of this module is to introduce the students to the current concepts for semiconductor-based nanoelectronics for quantum applications, with a focus on electrostatically defined quantum dots and donors as the elementary quantum bits (qubits). The module will introduce the basic physics, the fabrication and the operational principles of the these qubits and will discuss the current status of both approaches with respect, e.g., to relaxation, decoherence and scalability. For the manipulation of these qubits, magnetic resonance is used, which will be briefly reviewed.
Specific topics will include:
Review of fundamental semiconductor physics
crystal structure, band structure, excitons, dopants
Materials for semiconductor quantum electronics
Si, SiGe, III-V semiconductors including GaAs/AlGaAs, isotope engineering, heterostructures
Fabrication of devices for quantum electronics
molecular beam epitaxy, electron beam lithography, single ion implantation, STM lithography
Two-dimensional electron gases
electrostatics, diffusive and ballistic transport, g-factor
Review of spin physics
electron and nuclear spins, magnetic resonance, relaxation and decoherence
Electrostatically defined quantum dots
electronic transport, Coulomb diamond, single electron transistor, capacitance model, spin states, spin-to-charge conversion, Kondo effect
Spin interaction with the environment
spin orbit interaction, hyperfine interaction
Coupled quantum dots
electronic properties, spin blockade, hyperfine effects
Spin physics of dopants
g-factor, hyperfine coupling, quadrupole interaction
Electrically detected magnetic resonance
Single donor spins
readout via SET, coupling of donors, hyperfine effects
Comparison of quantum electronic systems discussed
topologies, quantum state transfers, the current state-of-the-art of such processors, challenges
Hybrid quantum systems
with microwaves, optical photons and/or phonons
After participation in the Module the student is able to:
- Understand the rationale for building semiconductor-based quantum electronic devices and circuits.
- Explain the fundamental principles of quantum-dot- and donor-based quantum bits, including the physics of two-dimensional electron gases.
- Understand which semiconductor nanostructures are used to generate, manipulate and detect electron and spin qubits, why they are used and how they are fabricated.
- Explain the fundamentals of magnetic resonance and its elementary pulse sequences.
- Sketch how these qubits are operated and what is observed.
- Understand how quantum processors are being developed from elementary one- and two-qubit systems.
- Understand and quantify the current limits of these qubits with respect to relaxation and decoherence.
- Judge new concepts for semiconductor-based qubits.
No preconditions in addition to the requirements for the Master's programs in Physics (Condensed Matter) or in Quantum Science and Technology.
Courses, Learning and Teaching Methods and Literature
Courses and Schedule
Learning and Teaching Methods
The module consists of a lecture.
Blackboard for the introduction of physical concepts and the quantitative analysis of effects, overhead projection for the discussion of experimental set-ups and results obtained, required reading of selected research publications.
Combined Power Point and blackboard presentation plus research publications.
- Thomas Ihn, Semiconductor Nanostructures, Oxford University Press
- Yuli Nazarov and Yaroslav M. Blanter, Quantum Transport, Cambridge University Press
- R. Hanson et al., Reviews of Modern Physics 79, 1217 (2007)
- Floris A. Zwanenburg et al., Silicon Quantum Electronics, Reviews of Modern Physics 85, 961 (2013)
- and topical research papers
Description of exams and course work
There will be an oral exam of 25 minutes duration. Therein the achievement of the competencies given in section learning outcome is tested exemplarily at least to the given cognition level using comprehension questions and sample calculations.
For example an assignment in the exam might be:
- How do you fabricate a quantum dot?
- With which accuracy can you place a single donor? Which technology would you use?
- What is spin diffusion and how can you suppress it?
- Sketch and explain the stability diagram of a coupled quantum dot!
- What are the pros and cons of using a heavier donor such as 75As as compared to 31P?
- How would you realize coherence transfer to a nuclear spin?
The exam may be repeated at the end of the semester.