Similarly to their purely electric counterparts, spintronic circuits may be presented as networks of lumped elements. Due to the interplay between spin and charge currents, each element is described ...by a matrix conductance. We establish reciprocity relations between the entries of the conductance matrix of a multiterminal linear device, comprising normal metallic and strong-ferromagnetic elements with vanishing spin-orbit interactions and spin-inactive interfaces. In particular, reciprocity equates the spin transmissions through a two-terminal element in opposite directions. When applied to "geometric spin ratchets," reciprocity shows that certain effects, announced for such devices, are, in fact, impossible. We describe the relation between our work and the spintronic circuit theory formalism and contrast our results with the requirements following from the Onsager symmetry of kinetic coefficients. Consequences of finite spin-orbit interactions are also discussed.
We show that, in a N\'eel antiferromagnet with a particular location of electron band extrema, a Skyrmion and an electron form bound states with energy of the order of the gap $\Delta$ in the ...electron spectrum. The bound states turn the Skyrmion into a charged particle, that can be manipulated by electric field.
There are two main theoretical descriptions of antiferromagnets. The first
arises from atomic physics, which predicts that atoms with unpaired electrons
develop magnetic moments. In a solid, the ...coupling between moments on nearby
ions then yields antiferromagnetic order at low temperatures.
The second description, based on the physics of electron fluids or 'Fermi
liquids', states that Coulomb interactions can drive the fluid to adopt
a more stable configuration by developing a spin density wave.
It is at present unknown which view is appropriate at a 'quantum critical
point', where the antiferromagnetic transition temperature vanishes. Here we report neutron scattering and bulk magnetometry
measurements of the metal CeCu6-xAux,
which allow us to discriminate between the two models. We find evidence for
an atomically local contribution to the magnetic correlations which develops
at the critical gold concentration (xc = 0.1
), corresponding to a magnetic ordering temperature of zero. This contribution
implies that a Fermi-liquid-destroying spin-localizing transition, unanticipated
from the spin density wave description, coincides with the antiferromagnetic
quantum critical point.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Most of solid-state spin physics arising from spin–orbit coupling, from fundamental phenomena to industrial applications, relies on symmetry-protected degeneracies. So does the Zeeman ...spin–orbit coupling, expected to manifest itself in a wide range of antiferromagnetic conductors. Yet, experimental proof of this phenomenon has been lacking. Here we demonstrate that the Néel state of the layered organic superconductor
κ
-(BETS)
2
FeBr
4
shows no spin modulation of the Shubnikov–de Haas oscillations, contrary to its paramagnetic state. This is unambiguous evidence for the spin degeneracy of Landau levels, a direct manifestation of the Zeeman spin–orbit coupling. Likewise, we show that spin modulation is absent in electron-doped Nd
1.85
Ce
0.15
CuO
4
, which evidences the presence of Néel order in this cuprate superconductor even at optimal doping. Obtained on two very different materials, our results demonstrate the generic character of the Zeeman spin–orbit coupling.
How do Fermi liquids get heavy and die? Coleman, P; Pépin, C; Si, Qimiao ...
Journal of physics. Condensed matter,
09/2001, Letnik:
13, Številka:
35
Journal Article
We revisit the question of whether a two-dimensional topological insulator may arise in a commensurate Néel antiferromagnet, where staggered magnetization breaks the symmetry with respect to both ...elementary translation and time reversal, but retains their product as a symmetry. In contrast to the so-called Z2 topological insulators, an exhaustive characterization of antiferromagnetic topological phases with the help of topological invariants has been missing. We analyze a simple model of an antiferromagnetic topological insulator and chart its phase diagram, using a recently proposed criterion for centrosymmetric systems 13. We then adapt two methods, originally designed for paramagnetic systems, and make antiferromagnetic topological phases manifest. The proposed methods apply far beyond the particular examples treated in this work, and admit straightforward generalization. We illustrate this by two examples of non-centrosymmetric systems, where no simple criteria have been known to identify topological phases. We also present, for some cases, an explicit construction of edge states in an antiferromagnetic topological insulator.
We revisit the question of whether a two-dimensional topological insulator may arise in a commensurate Neel antiferromagnet, where staggered magnetization breaks the symmetry with respect to both ...elementary translation and time reversal, but retains their product as a symmetry. In contrast to the so-called Z.sub.2 topological insulators, an exhaustive characterization of antiferromagnetic topological phases with the help of topological invariants has been missing. We analyze a simple model of an antiferromagnetic topological insulator and chart its phase diagram, using a recently proposed criterion for centrosymmetric systems 13. We then adapt two methods, originally designed for paramagnetic systems, and make antiferromagnetic topological phases manifest. The proposed methods apply far beyond the particular examples treated in this work, and admit straightforward generalization. We illustrate this by two examples of non-centrosymmetric systems, where no simple criteria have been known to identify topological phases. We also present, for some cases, an explicit construction of edge states in an antiferromagnetic topological insulator.
We revisit the question of whether a two-dimensional topological insulator may arise in a commensurate Néel antiferromagnet, where staggered magnetization breaks the symmetry with respect to both ...elementary translation and time reversal, but retains their product as a symmetry. In contrast to the so-called
Z
2
topological insulators, an exhaustive characterization of antiferromagnetic topological phases with the help of topological invariants has been missing. We analyze a simple model of an antiferromagnetic topological insulator and chart its phase diagram, using a recently proposed criterion for centrosymmetric systems 13. We then adapt two methods, originally designed for paramagnetic systems, and make antiferromagnetic topological phases manifest. The proposed methods apply far beyond the particular examples treated in this work, and admit straightforward generalization. We illustrate this by two examples of non-centrosymmetric systems, where no simple criteria have been known to identify topological phases. We also present, for some cases, an explicit construction of edge states in an antiferromagnetic topological insulator.
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