Experiments during Wintersemester 2022
E-Mail: kng (at) pi5.physik.uni-stuttgart.de
Room: 1.570 Tel.: 64849
A better understanding of material properties allows us to manipulate them and create new compounds with better electronic, mechanic and optical properties. However such an understanding requires the knowledge of the detailed structure of the materials, because without this knowledge one is as lost as in unknown territory without a map. With X-ray diffraction structural parameters of crystalline materials can be determined with high precision. In this experiment the basic principles of X-ray diffraction are developed. For this purpose in the first part of the experiment the properties of X-rays and their absorption characteristics are investigated with an X-ray apparatus. In the second part the structural properties and parameters of single crystals are determined with X-ray diffraction.
Generation and absorption of X-rays, crystalline structure, lattice, reciprocal lattice, Bragg reflection, Laue equations, X-ray tubes, counter tube, Compton effect, x-ray fluorescence.
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: 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.