Homepage Peter C.M. Christianen

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Research Interests

Semiconductor and organic nanostructures in high magnetic fields

In the currently available highest magnetic fields the magnetic length, i.e. the quantum mechanical size of an electron orbit, becomes comparable to the dimensions of modern nanostructures. High field experiments on nano-objects can therefore provide insight on their electronic, optical, magnetic and structural properties. In recent years we have developed a microscopic imaging set-up that is capable of measuring individual nanostructures in fields up to 33 T. This set-up was used to follow the transport of neutral and charged excitons in semiconductor quantum wells, as well as their energy spectrum in high magnetic fields. Currently we are using the technique for imaging individual nano-objects, such as semiconductor quantum dots, small organic molecules, single enzymes and self-assembled nanofibers and -capsules. These single-object measurements provide new information which is complementary to the results of our regular optical, magnetometry or transport experiments on ensembles of nanostructures, the signal of which is averaged over a large number of objects.

Highlights

Aharonov-Bohm Oscillations in Semiconductor Quantum Rings

First optical experiments at 52T First light at 52T

Polarized emissison of self-assembled nanofibers Polarized emission from self-assembled nano-fibers

Semiconductor Light Emitters Feel the Force.

Magnetic manipulation of Molecular Matter

Strong magnetic fields are a versatile tool to exert non-invasive, well-known forces in order to manipulate a wide range of different materials. Since most matter is diamagnetic there are many possibilities to use magnetic forces, provided the highest magnetic fields are available. Magnetic levitation can be used for the contact less separation of substances or to simulate micro-gravity conditions, allowing experiments like the growth of crystals, which otherwise only can be performed in space-missions. Magnetic alignment is a powerful method to induce orientational order in anisotropic materials, such as polymers, molecular aggregates, nanocolloids and liquid crystals, and can lead to improved physical properties of the material or to facilitate their investigation. Particularly interesting is the ability to control matter at a molecular- or nano-scale, and to combine magnetic forces with supramolecular or colloidal self-assembly, which is crucial for the development and understanding of novel materials with new functionalities.

Highlights

Elasticity of Molecular Nanocapsules

growing crystals in microgravity Crystal growth in microgravity

Deformation of spherical nanocapsules