Switchable Fermi surface sheets in greigite

Switchable Fermi surface sheets in greigite

Switchable surface structured hydrogel coatings.

Switchable surface structures based on hydrogels are an emerging field in material science, microfluidics, soft robotics and anti-fouling. Here, we describe a novel method that uses a photo-cross-linkable terpolymer to create a hydrogel coating with a switchable surface structure. The terpolymer is based on poly(N-isopropylacrylamide) (PNIPAm) and it is shown that simple coating technologies li...

Fermi surface of NaxCoO2.

Doping evolution of the Fermi surface topology of Na(x)CoO(2) is studied systematically. Both local density approximation (LDA) and local spin density approximation (LSDA) predict a large Fermi surface as well as small hole pockets for doping levels x approximately 0.5. In contrast, the hole pockets are completely absent for all doping levels within LSDA+U. More importantly, we find no violatio...

Anomalous Chiral Fermi Surface

We provide a geometrical argument for the emergence of a Wess-Zumino-Witten (WZW) term in a Fermi surface threaded by a Berry curvature. In the presence of external fields, the gauged WZW term yields a chiral (triangle) anomaly for the fermionic current at the edge of the Fermi surface. Fermion number is conserved though since Berry curvatures occur always in pairs with opposite (monopole) char...

Fermi surface distortionst

The energy independent model pseudopotential (EIMP) formalism, developed in the preceding paper, and Shaw’s optimized model potential (OMP) formalism are applied to first principles calculations of phonon spectra of the alkali metals and AI and of Fermi surface distortions for the alkali metals. Then the applicability of the EIMP formalism for calculating actual physical quantities needed to ch...