Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 77: Transport in High Magnetic Fields
HL 77.5: Vortrag
Donnerstag, 23. März 2017, 16:00–16:15, POT 112
Calculations of Quantum Capacitance of The Two Dimensional Electron System — •Eren Güvenilir1, Özge Kiliçoğlu2, Afif Siddiki3, and Deniz Eksi4 — 1Istanbul Technical University, Istanbul, Turkey — 2Işik University, Istanbul, Turkey — 3Mimar Sinan Fine Arts University, Istanbul, Turkey — 4Yeni Yuzyil University, Istanbul, Turkey
In this work we investigate the electrostatic properties of two dimensional electron system (2DES) in the integer quantum Hall regime. The alternating screening properties of the compressible and the incompressible strips are formed due to edge effects. We consider the effects of impurities on the 2DES via density of states calculations. As it is well known, the Landau Levels emerge due to strong perpendicular magnetic field and the levels are broadened which stem from impurities. At a first order approximation the density of state takes two different forms when considering impurities, these are the Gaussian and the semi-elliptic forms calculated within the self consistent Born approximation. Having in hand the density of states, we calculate both the longitudinal and Hall conductivities utilizing Thomas-Fermi-Poisson approximation. Since, the definition of capacitance is closely related with the charging energy; the compressibility of 2DES is extremely important. Here we numerically simulate the experimental observations and can predict local capacitance. We obtained numerically the local capacitances of a 2DES subject to perpendicular magnetic field. Our findings are in perfect agreement with the experiment which is based on a dynamic scanning capacitance microscopy.