TiPtSi
Metal silicide contacts to the source, drain and gate of field effect transistors have played a key role in the electronic technology. In our studies we focus on PtSi. Among some general advantages of using metal silicides as contact materials (e.g. self-aligning contacts) PtSi has relatively low (0.2 eV) Schottky barriers on Si (001) and exhibits excellent thermal stability. However, PtSi suffers of relatively low conductivity which can be traced to the low density of states (DOS) of bulk PtSi at the Fermi-level. We manipulate the DOS at the Fermi-level by doping with Ti and analyze the influence on the conductivity of the alloys. We estimate formation energies and the entropic effect of mixing of the alloys to study their thermodynamic stability. In ongoing studies we focus on possible schemes to improve the stability properties of the alloys and calculate their workfunction for different orientations.QMC
A very successful method of calculating electronic properties of atoms, molecules and solids is given by Quantum Monte Carlo (QMC) methods. QMC is an attempt to treat the exact many-electron Hamiltonian by using a variational trial wave function and relies on probabilistic methods. Although computationally very demanding the computed physical properties are usually within tenths of percentages of the corresponding experimentally measured values. Beginning with the rather intuitive approach of Variational Monte Carlo many different improved Monte Carlo methods can be found in literature. As a part of my Master thesis we developed a Monte Carlo code. The posted plots show qualitatively the electronic (blue) and ionic (red) charge density of an H2 molecule oriented along the x-axis using hydrogen-like px and py orbitals (as indicated in the plots). However, in the ongoing study our goal is to investigate the electronic properties of water.