Spin-ensemble density-functional theory for inhomogeneous quantum Hall systems

Ensemble Density Functional Theory for Inhomogeneous Fractional Quantum Hall Systems

Transverse spin-gradient functional for noncollinear spin-density-functional theory.

We present a novel functional for spin-density-functional theory aiming at the description of noncollinear magnetic structures. The construction of the functional employs the spin-spiral-wave state of the uniform electron gas as reference system. We show that the functional depends on transverse gradients of the spin magnetization; i.e., in contrast with the widely used local spin density appro...

Density Functional Theory of Spin-Polarized Disordered Quantum Dots

Using density functional theory, we investigate fluctuations of the ground-state energy of spin-polarized, disordered quantum dots in the metallic regime. To compare to experiment, we evaluate the distribution of addition energies and find a convolution of the Wigner-Dyson distribution, expected for noninteracting electrons, with a narrower Gaussian distribution due to interactions. The third m...

Spin-Density-Functional Theory of Circular and Elliptical Quantum Dots

Using spin-density-functional theory, we study the electronic states of a two-dimensional parabolic quantum dot with up to N = 58 electrons. We observe a shell structure for the filling of the dot with electrons. Hund’s rule determines the spin configuration of the ground state, but only up to 22 electrons. At specific N , the ground state is degenerate, and a small elliptical deformation of th...

Spin in fractional quantum Hall systems

A system at filling factor 2/3 could be a candidate for a quantum Hall ferromagnet at integer filling factor of composite fermions. Using exact diagonalization with electrons on a torus we study the transition from the singlet ground state to the polarized ground state at this filling and look for signatures of quantum Hall ferromagnetism. Differences between the fractional and corresponding in...