The spin Nernst effect is a phenomenon of spin current generation caused by the thermal flow of

electron The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up qua ...

s or magnons in condensed matter. Under a thermal drive such as

temperature gradient A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature spatial gradient is a vector quantity with Dimensional analysis, ...

chemical potential In thermodynamics, the chemical potential of a Chemical specie, species is the energy that can be absorbed or released due to a change of the particle number of the given species, e.g. in a chemical reaction or phase transition. The chemical potent ...

gradient, spin-up and spin-down carriers can flow perpendicularly to the thermal current and towards opposite directions without the application of a

magnetic field A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...

. This effect is similar to the

spin Hall effect The spin Hall effect (SHE) is a transport phenomenon predicted by Russian physicists Mikhail I. Dyakonov and Vladimir I. Perel in 1971. It consists of the appearance of Spin (physics), spin accumulation on the lateral surfaces of an electric cur ...

, where a pure spin current is induced by an

electrical current Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

. The spin Nernst effect can be detected by the spatial separation of opposite spin species, typically in the form of

spin polarization In particle physics, spin polarization is the degree to which the spin, i.e., the intrinsic angular momentum of elementary particles, is aligned with a given direction. This property may pertain to the spin, hence to the magnetic moment, of co ...

(imbalanced spin accumulation) on the transverse boundaries of a material. The spin Nernst effect of electrons was first experimentally observed in 2016 and published by two independent groups in 2017. The spin Nernst effect of magnons (quanta of

spin wave In condensed matter physics, a spin wave is a propagating disturbance in the ordering of a magnetic material. These low-lying collective excitations occur in magnetic lattices with continuous symmetry. From the equivalent quasiparticle point of ...

excitations) was theoretically proposed in 2016 in collinear antiferromagnetic materials, but its experimental confirmation remains elusive. In 2017, around the same time when its electronic counterpart was experimentally observed, the spin Nernst effect of magnons was first claimed in transition metal trichalcogenide MnPS₃. However, the experiment involved ambiguities that cannot convincingly verify the spin Nernst effect of magnons, awaiting further experimental studies. With a more accurate description accounting for real device geometry, it was believed that optical detection should be more reliable than electronic detection. At present, optical detection of the spin Nernst effect of magnons has not been reported.

References

{{reflist Condensed matter physics Spintronics Walther Nernst

See also

References