In this work we study the effect of the rare earth element in iron oxypnictides of composition REFeAsO (RE=rare earth). On one hand we carry out density functional theory calculations of the band structure, which evidence the multiband character of these compounds and the presence of Dirac cones...

The resistivity of boron doped polycrystalline diamond films changes with boron content in a very complex way with many unclear factors. From the large number of parameters affecting boron doped polycrystalline diamond film’s conductivity we focused on the role of boron atoms inside diamond...

We study anisotropic stripe models of interacting electrons in the presence of magnetic fields in the quantum Hall regime with integer and fractional filling factors. The model consists of an infinite strip of finite width that contains periodically arranged stripes (forming supercells) to which...

Multiferroic rare-earth manganites are theoretically studied by focusing on the coupling to the lattice degrees of freedom. We demonstrate analytically that the phonon excitations in the multiferroic phase are strongly affected by the magnetoelectric coupling, the spin-phonon interaction and the...

Specific heat and magnetization measurements demonstrate that the antiferromagnetic (AFM) phase transition at T <Subscript> N </Subscript> = 5.7 K of EuTiO<Subscript>3</Subscript> is rapidly suppressed with Sr doping in Eu<Subscript> x </Subscript>Sr<Subscript>1−x </Subscript>TiO<Subscript>3</Subscript>. Close to x = 0.25, T <Subscript> N </Subscript> = 0 K and AFM order vanishes. Above this critical concentration a...</subscript></subscript></subscript></subscript></subscript></subscript>

The need of alternative “green” energy sources has recently renewed the interest in thermoelectric (TE) materials, which can directly convert heat to electricity or, conversely, electric current to cooling. The thermoelectric performance of a material can be estimated by the so-called figure...

We analyze electron transport in multiprobe quantum spin Hall (QSH) bars using the Büttiker formalism and draw parallels with their quantum Hall (QH) counterparts. We find that in a QSH bar the measured resistance changes upon introducing side voltage probes, in contrast to the QH case. We also...

We use the Schwinger boson mean field theory to study the effect of frustration and dimerization in the quantum ferrimagnetic model in one and two-dimensions. We calculate the spin reduction, the gap of the antiferromagnetic branch, and the spin fluctuation at T = 0 K. At finite temperature,...

We predict resistance anomalies to be observed at high-mobility two-dimensional electron systems (2DESs) in the fractional quantized Hall regime, where the narrow (L  10 μm) Hall bar is defined by top gates. A semi-analytic calculation scheme is used to describe the formation of integral and...

Nickel oxide thin films were prepared by thermal annealing of thin Ni films (thickness ca 47 nm) deposited by ion beam sputtering. The thermal annealing was performed at 350 °C and 400 °C with elected time (1–7 hours) in a quartz furnace opened to air. During annealing the samples...