gharib85/5thyearproject

Archive of work and results from my master's project, 'Simulating the Effects of phonons on 2D Quantum Devices.'

Practical quantum technologies rely on robust hardware. For many applications, semiconductor quantum nanostructures are ideal candidates, e.g. as physical implementations of quantum bits, or as emitters of non-classical light. However, phonons, i.e. vibrations in the underlying crystal structure, severely change the behaviour and operation of semiconductor quantum devices in ways that - in many cases - we do not yet fully understand. A novel class of promising nanostructures is based on two-dimensional materials such as graphene (the exploration of which awarded the Nobel Prize in 2010) and MoS2 (molybdenum disulfide).

Surprisingly, the effects of phonons on quantum devices are largely determined by a single function, the so-called phonon spectral density. While analytic approximations to the spectral density are known for many conventional physical structures, the same is not the case for 2D material due to a number of additional and unusual features in their electron and phonon band structures.

The goal of this project is to develop the tools necessary to derive phonon spectral densities for different materials based on an approach called an atomistic valence force-field model. This will first be explored using open quantum systems and their effect on spectral densities. This will be studied analytically and numerically, with the numerical interactions of spectral densities and phonons then implemented. We are hoping to trial and benchmark this technique first on conventional semiconductors and then move on to predict phonon effects in 2D materials.