Max Bichler

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Electrostatic coupling between particles is important in many microscopic phenomena found in nature. The interaction between two isolated point charges is described by the bare Coulomb potential, but in many-body systems this interaction is modified as a result of the collective response of the screening cloud surrounding each charge carrier. One such(More)
The spin of a single electron subject to a static magnetic field provides a natural two-level system that is suitable for use as a quantum bit, the fundamental logical unit in a quantum computer. Semiconductor quantum dots fabricated by strain driven self-assembly are particularly attractive for the realization of spin quantum bits, as they can be(More)
Present-day information technology is based mainly on incoherent processes in conventional semiconductor devices. To realize concepts for future quantum information technologies, which are based on coherent phenomena, a new type of 'hardware' is required. Semiconductor quantum dots are promising candidates for the basic device units for quantum information(More)
Quantum mechanical experiments in ring geometries have long fascinated physicists. Open rings connected to leads, for example, allow the observation of the Aharonov-Bohm effect, one of the best examples of quantum mechanical phase coherence. The phase coherence of electrons travelling through a quantum dot embedded in one arm of an open ring has also been(More)
An electron-phonon cavity consisting of a quantum dot embedded in a freestanding GaAs/AlGaAs membrane is characterized using Coulomb blockade measurements at low temperatures. We find a complete suppression of single electron tunneling around zero bias leading to the formation of an energy gap in the transport spectrum. The observed effect is induced by the(More)
Spin-sensitive bleaching of the absorption of far-infrared radiation has been observed in p-type GaAs/AlGaAs quantum well structures. The absorption of circularly polarized radiation saturates at lower intensities than that of linearly polarized light due to monopolar spin orientation in the first heavy-hole subband. Spin relaxation times of holes in p-type(More)
A pair of interdigitated gates, interlacing off center, is used to generate a widely tunable one-dimensional lateral superlattice in the two-dimensional electron gas at a GaAs/AlGaAs heterointerface. Magnetotransport measurements with statically biased gates demonstrate that the conduction-band modulation is strongly influenced by higher harmonics, thus(More)
We present magnetotransport measurements on freely suspended two-dimensional electron gases from Al x Ga 1Ϫx As/GaAs heterostructures. The technique to realize such devices relies on a specially molecular beam epitaxy grown GaAs/Al x Ga 1Ϫx As-heterostructure, including a sacrificial layer. We fabricated simple mini-Hall-bars as well as quantum cavities and(More)
Core-shell nanowires (NW) have become very prominent systems for band engineered NW heterostructures that effectively suppress detrimental surface states and improve performance of related devices. This concept is particularly attractive for material systems with high intrinsic surface state densities, such as the low-bandgap In-containing group-III(More)
We discuss geochemical and sedimentological characteristics of 12 tephra layers, intercalated within the finely laminated sediments of Lake Van. Within the about 15kyr long sediment record studied, volcanic activity concentrated in the periods 2.6-7.2 and 11.9-12.9kyr B.P. Concentrations of 25 elements provide the geochemical fingerprint of each tephra(More)