Scanning Tunnelling Microscopy (STM) is a well established and widely used technique in the world of surface physics, capable of measuring atomic resolution topographs within seconds. There are...Show moreScanning Tunnelling Microscopy (STM) is a well established and widely used technique in the world of surface physics, capable of measuring atomic resolution topographs within seconds. There are however still improvements we can make. Where spatial resolution is almost perfect, the temporal resolution of STM is quite terrible, limiting the measurement of rapid fluctuations in the tunnelling current. This withholds STM from for example measuring shotnoise and single atom spin relaxation. We try to solve this issue by designing a small cryogenic amplifier and implementing it close to the tip of a STM setup, increasing its bandwidth around 2.8MHz. We discus simulations as well as test results from our amplifier. Finally, we give an outlook on how to improve this design in order to measure shotnoise.Show less
In BCS superconductors the critical temperature is dependent on the phonon dispersion relation. We want to influence - and hopefully increase - the critical temperature by varying the phonon...Show moreIn BCS superconductors the critical temperature is dependent on the phonon dispersion relation. We want to influence - and hopefully increase - the critical temperature by varying the phonon dispersion. This can be done by altering the lattice structure of a material on the nanoscale using nanofabrication. As a proof-of-principle project we simulate these phonon structures and see whether or not higher critical temperatures come out. In this project we tested the code for mistakes and physical inaccuracies. The code reproduced physical effects correctly, but artificial parameters which we need to put in because of numerics issues have some influence on the outcomes. However, we think this is not a big problem because in the end we calculate the ratio of critical temperatures between two systems. This means that all that is constant in the whole calculation will be divided out.Show less
Physicists like to find out how things work on the smallest level. When doing experiments in which we want to achieve atomic resolution, there are many factors that can influence the experiments,...Show morePhysicists like to find out how things work on the smallest level. When doing experiments in which we want to achieve atomic resolution, there are many factors that can influence the experiments, for example: thermal fluctuation and external vibrations. The latter is what we focused on during this project. At the Leiden Institute of Physics we have built a new low vibration laboratory in order to perform experiments that can achieve atomic resolution. In this report we will describe and compare the vibrations in both the old and new low vibration laboratory. We have found that the vibrations in the new laboratory are much less and that this new lab is comparable with some of the most successful scanning tunneling microscopy laboratories in the world.Show less
