arXiv subjects

K. Esfarjani

Publications and source records attributed to K. Esfarjani.

4 recordsLinked to original sources

arXiv2006

Localization-delocalization transition in a one-dimensional system with long-range correlated off-diagonal disorder

The localization behavior of the one-dimensional Anderson model with correlated and uncorrelated purely off-diagonal disorder is studied. Using the transfer matrix method, we derive an analytical expression for the localization length at the band center in terms of the pair correlation function. It is proved that for long-range correlated hopping disorder, a localization-delocalization transition occurs at the critical Hurst exponent H_c= 1/2 when the variance of the logarithm of hopping "σ_{\ln(t)}" is kept fixed with the system size N. Based on numerical calculations, finite size scaling relations are postulated for the localization length near the band center (E \neq 0) in terms of the system parameters: E,N,H, and σ_{\ln(t)}.

cond-mat.dis-nn↗

arXiv2006

Magnetism near the metal-insulator transition in two-dimensional electron systems: the role of interaction and disorder

Recent thermodynamic measurements on two-dimensional (2D) electron systems have found diverging behavior in the magnetic susceptibility and appearance of ferromagnetism with decreasing electron density. The critical densities for these phenomena coincide with the metal-insulator transition recorded in transport measurements. Based on density functional calculations within the local spin-density approximation, we have investigated the compressibility and magnetic susceptibility of a 2D electron gas in the presence of remote impurities. A correlation between the minimum in the inverse capacitance ($\partialμ/\partial n$) and the maximum of magnetization and magnetic susceptibility is found. Based on values we obtain for the inverse participation ratio, this seems to be also the MIT point.

cond-mat.str-el↗

arXiv2001

Statics and dynamics of phase segregation in multicomponent fermion gas

We investigate the statics and dynamics of spatial phase segregation process of a mixture of fermion atoms in a harmonic trap using the density functional theory. The kinetic energy of the fermion gas is written in terms of the density and its gradients. Several cases have been studied by neglecting the gradient terms (the Thomas-Fermi limit) which are then compared with the Monte-Carlo results using the full gradient corrected kinetic energy. A linear instability analysis has been performed using the random-phase approximation. Near the onset of instability, the fastest unstable mode for spinodal decomposition is found to occur at $q=0$. However, in the strong coupling limit, many more modes with $q\approx K_F$ decay with comparable time scales.

physics.atm-clus↗

arXiv2000

Realization of an ultra-high magnetic field on a nano-scale

In tunnel junctions of which at least one side is a ferromagnet, very large magnetic polarization change ($\approx 0.1 μ_B$) and splitting of the spin up and spin down Fermi energy ($\approx 0.1 eV$) can be created under steady state finite current conditions (bias voltage $\approx$ 1 volt). This is {\bf much higher} than can be created by the highest magnetic field on earth. We illustrate this with a specific calculation of a recently observed very large Hall effect in the Al side of a Co-I-Al tunnel junction. Other recent experiments that support this idea are discussed.

cond-mat.mtrl-sci↗