The aim of this project is to prepare clean surfaces and ultrathin layers of van-der-Waals crystals for spectroscopic analysis. Using the method of mechanical exfolation the upper layers of the crystals will be removed and transfered onto thin gold films. The quality of the produces surfaces will be analyses with typical surface science methods.

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Learnt Methods:

• Mechanical Exfoliation
• Low-Energy Electron Diffraction (LEED)
• Scanning Electron Microscopy (SEM)
• Auger-Electron Spectroscopy (AES)

In this project, novel Dirac and Weyl semimetals will be characterized using infrared and Raman spectroscopy. These materials exhibit characteristic signatures in their optical conductivity, which can be determined through reflectivity measurements. To perform these measurements, preparation of the sample surface via polishing is required.

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Learnt Methods:

• Sample surface preparation by polishing with diamond films

• Infrared spectroscopy

• Raman spectroscopy

In this project, novel quantum materials that can exhibit magnetic or charge ordering upon cooling are to be characterized. These temperature-induced phase transitions will be investigated using infrared spectroscopy. By performing reflectivity measurements over a broad frequency range, the optical conductivity can be determined, which contains vital information about lattice dynamics and electronic excitations. From the optical conductivity, important conclusions can be drawn regarding temperature-dependent phase transitions.

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Learnt Methods:

• Infrared spectroscopy

• Handling of high-vacuum systems

• Cooling with liquid helium

Novel quantum materials often exhibit exotic phases when subjected to high external pressure. In this project, high external pressures are to be generated using diamond anvil cells. The pressure-induced phases in the material will be investigated using infrared spectroscopy, which provides insights into the lattice dynamics and electronic excitations of materials.

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Learnt Methods:

• Diamond anvil cells (DAC)

• Infrared spectroscopy

By applying uniaxial pressure, the crystal symmetry of materials can be broken, which can lead to significant changes in their optical properties. In this project, the optical properties of novel materials under uniaxial pressure are to be investigated. Of particular interest are the lattice dynamical properties and optical excitations, which can exhibit anomalous behavior under uniaxial pressure.

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Learnt Methods:

• Handling of uniaxial pressure cells

• Reflectivity measurements over a broad frequency range

• Raman scattering