Magnetic-field-induced changes of the Fermi surface play a central role in theories of the exotic quantum criticality of YbRh2Si2. We have carried out de Haas-van Alphen measurements in the magnetic-field range 8 T < or = H < or = 16 T, and directly observe field dependence of the extremal Fermi surface areas. Our data support the theory that a low-field "large" Fermi surface, including the Yb ...

The paper discusses relations between the structure of the complex Fermi surface below the spectrum of a second order periodic elliptic equation and integral representations of certain classes of its solutions. These integral representations are analogs of those previously obtained by S. Agmon, S. Helgason, and other authors for solutions of the Helmholtz equation (i.e., for generalized eigenfu...

Fermi surface models applied to the underdoped cuprates predict the small pocket area to be strongly dependent on doping whereas quantum oscillations in YBa(2)Cu(3)O(6+x) find precisely the opposite to be true--seemingly at odds with the Luttinger volume. We show that such behavior can be explained by an incommensurate antinodal Fermi surface nesting-type instability--further explaining the dop...

The transition metal dichalcogenide 1T-TaS2 is a layered material exhibiting charge density waves. Based on angleresolved photoemission experiments mapping spectral weight at the Fermi surface and density functional theory calculations we discuss possible mechanisms involved with the creation of charge density waves. At first the flat parts of the elliptically shaped Fermi surface appear to pla...

The Fermi surface of most hole-doped cuprates is close to a Van Hove singularity at the M point. A two-dimensional electronic system, whose Fermi surface is close to a Van Hove singularity, shows a variety of weak coupling instabilities. It is a convenient model to study the interplay between antiferromagnetism and anisotropic superconductivity. The renormalization group approach is reviewed wi...

we describe an approach to the theory of the Fermi surface based on the renormalization group. A notion of quasi particle appears naturally in the theory. The beta function is finite to all orders of perturbation theory and we compute and discuss it to second order. The normality of the Fermi surface is linked to the repulsivity of the quasi particle potential: the remarkable cancellations that...

Fermi arcs are the surface manifestation of the topological nature of Weyl semimetals, enforced by the bulk-boundary correspondence with the bulk Weyl nodes. The surface of tantalum arsenide, similar to that of other members of the Weyl semimetal class, hosts nontopological bands that obscure the exploration of this correspondence. We use the spatial structure of the Fermi arc wave function, pr...

Fermions in a Fermi gas obey the Pauli exclusion principle restricting any two fermions from occupying same quantum state. Strong interactions between can completely change properties of gas. In our theoretical study we find an exotic phase strongly interacting gases subject to certain condition imposed on surfaces that call surface resonance. The is critical time and space be identified by pow...

Using Auger electron spectroscopy and x-ray photoelectron spectroscopy we show that the unpinned GaAs is covered by a Ga203 layer with only small amounts of species containing arsenic. This oxide is formed by the consumption of GaAs during the unpinn ing treatment. We believe that it is this oxide that passivates the surface, allowing it to remain near flatband for several hours in room air. Th...