Browsing by Subject "Ground state energy"

Now showing 1 - 3 of 3

Open Access
Analytic calculation of ground state properties of the 2d and 3d electron gas
(2015-06) Katı, Yağmur
The electron gas (2D and 3D) is a model which consists of interacting electrons moving in a uniform positive background. Its importance stems from the fact that a number of metals behave similarly, it provides the functional used in density functional theory, and that in 2D it can be experimentally realized. Understanding the behavior of this model is of fundamental importance. In this thesis we present an analysis of this model based on the Hypernetted Chain Method in 3D, and 2D. The HNC method is a variational method to calculate the ground state properties of an interacting system, by expressing the ground state energy as a functional of the radial distribution function. Minimizing the energy expression one obtains a zero energy Schr odinger equation for the square root of the radial distribution function. The potential in this equation can include the e ects of fermionic or bosonic exchange. We applied this method to charged boson and electron gas in 2D and 3D systems. On the basis of the results of this research, it can be concluded that we obtained very close correlation energy results compared to Monte Carlo, and FHNC results for the density range when rs is from 0 to 20. This extended range is important for solid state applications.
Open Access
Compressibility of a two-dimensional electron gas in a parallel magnetic field
(Elsevier B.V., 2007) Subaşi, A. L.; Tanatar, Bilal
The thermodynamic compressibility of a two-dimensional electron system in the presence of an in-plane magnetic field is calculated. We use accurate correlation energy results from quantum Monte Carlo simulations to construct the ground state energy and obtain the critical magnetic field Bc required to fully spin polarize the system. Inverse compressibility as a function of density shows a kink-like behavior in the presence of an applied magnetic field, which can be identified as Bc. Our calculations suggest an alternative approach to transport measurements of determining full spin polarization.
Open Access
Superconductivity in ultrasmall metallic particles
(Springer, 2000) Boyacı, Hüseyin; Gedik, Zafer; Kulik, Igor O.; Kulik, Igor O.; Ellialtıoğlu, Recai
Recent single electron transport experiments in nanometer size samples renewed the question about the lower limits of the size of superconductors, and the crossover from superconducting to normal state. In order to give answers to these questions, a pairing Hamiltonian for fixed number of particles is studied including the degeneracy of levels around the Fermi energy. For d-fold degenerate states we find that the ratio of two successive parity parameters Δ p is nearly 1 + l/d.