Experiments during Sommersemester 2022
E-Mail: ponraj.vijayan (at) ihfg.uni-stuttgart.de
Room: 1.905 Tel.: 64869
The Hall-Effect is an important method for the characterisation of metals and semiconductors. From Hall-measurements one gain information about the electrical parameters of a semiconductor, like the mobility, the charge carrier density and the band gap. In the students lab you measure the Hall voltage in dependence of temperature, magnetic field and the longitudinal current of an undoped and p-doped Ge-crystal. Consequential you can deduce the relevant parameter like band gap, electron and hole mobility as well as their particular densities. Key words: Band structure of a semiconductor; Transport in semiconductors; Charge carrier mobility in an electron gas; Scattering and relaxation; Doping; Magneto-transport and Hall-Effect
Institute: MPI FKF
E-Mail: K.Rabinovich (at) fkf.mpg.de
Room: 1.909 Tel.: 64871
Quantum Analogs is an acoustical experiment designed to explain wave mechanics. The basis of the experiment is the analogy between the mathematical description of an electron in a potential (Schrödinger equation) und the behavior of ordinary sound waves in air (Helmholtz equation). The major advantage of acoustical experiments hereby is that sound-phenomena appear on an accessible time and length scale for humans. The experimental setup allows to investigate acoustical analogies with one- and three-dimensional quantum mechanical systems. Acoustical analogues to the hydrogen atom and hydrogen molecule and the dispersion in one-dimensional acoustical semiconductors are examined.
Schrödinger equation, hydrogen atom, hydrogen molecule, Bragg condition, band gap, reciprocal space, dispersion relation, Brillouin zone, reduced zone scheme
E-Mail: d.dzhavadzade (at) pi3.uni-stuttgart.de
Room: 1.519 Tel.: 64813
Today nuclear magnetic resonance (NMR) is one of the most important spectroscopic methods in physics, chemistry, biology and medicine. It provides information about the electronic environment of single atoms and their interactions with neighbouring atoms. This information allows the analysis of the structure and dynamic of the sample. The measuring principle of cw- and pulsed NMR is shown with a simple spectrometer. The characteristic values T1 (spin-lattice relaxation time) and T2 (spin-spin relaxation time) are determined for selected samples.
classical and quantum mechanical description of nuclear magnetic resonance, pulse-NMR (rotating coordinate system, FID, spin echo, pulse sequences), measurement of T1 and T2 (spin-spin relaxation, spin-lattice relaxation)
E-Mail: v.vorobyov (at) pi3.uni-stuttgart.de
Room: 1.921 Tel.: 64876
Noise ultimately determines the sensitivity limit in all physical measurements. There is no measuring system that is free of statistical fluctuations. In measurements of current and voltage this fluctuations originate from the finite size of the elementary electric charge (shot noise) or the thermal motion of the charge carriers (thermal noise). An exact noise analysis thus allows the precise measurement of the elementary electric charge e- and the Boltzmann constant kB. Therefore in this experiment noise itself is the investigated signal.
E-Mail: anasuri (at) pi5.physik.uni-stuttgart.de
Room: 1.934 Tel.: 64862
Optical pumping allows to probe atomic phenomena such as resonant light absorption, nuclear spin energy levels, Zeemann splitting and Rabi oscillations. The fundamental idea of optical pumping is to use polarized light to create an energy population distribution that is different from the Boltzmann distribution at a given temperature. In the experimental setup gaseous Rubidium is pumped, which has a hydrogen-like electronic configuration but consists of two isotopes with different nuclear spins leading to manifold lines.