Search Results for « Intrinsic thermal Hall effect »

Abstract In this paper, we study the intrinsic contribution of nonlinear magnon thermal Hall Effect. We derive the intrinsic second-order thermal Hall conductivity of magnon by the thermal scalar potential method and the thermal vector potential method. We find that the intrinsic second-order magnon thermal Hall conductivity is related to the thermal Berry-connection polarizability. We apply our theory to the monolayer ferromagnetic Hexagonal lattice, and we find that the second-order magnon thermal Hall conductivity can be controlled by changing Dzyaloshinskii–Moriya strength and applying strain.

Spin-gapless semiconductors (SGSs) have become an important topic in spintronics because they combine zero-gap electronic features with complete spin polarization, offering opportunities for low-dissipation transport and high-efficiency spin manipulation. This makes them natural candidates for hosting topological states such as the quantum anomalous Hall (QAH) phase. In this work, we show that honeycomb monolayer Zr 2 O 6 belongs to a ferromagnetic QAH insulator. Without spin–orbit coupling, Zr 2 O 6 shows linear band crossings (BCs) near the Fermi level (E F ) only in the spin-down sector, whereas the spin-up sector remains gapped, giving rise to SGS nature. SOC then opens a gap for the bands of spin-up sector, and drives the system into a insulating state with C = −1, making Zr 2 O 6 a good candidate for investigating the QAH physics.

Abstract In recent years, the spin Hall effect has been received great attention because of its potential application in spintronics and quantum information processing and storage. However, this effect is usually studied under the external homogeneous electric field. Understanding how the inhomogeneous electric field affects the spin Hall effect is still lacking. Here, we give the general expression for the intrinsic spin Hall conductivity in the presence of the inhomogeneous electric field, which is shown to be expressed through gauge-invariant geometric quantities. On the other hand, when people get physical intuition on transport phenomena from the wave packet, one issue appears. It is shown that the conductivity obtained from the conventional wave packet approach cannot be fully consistent with the one predicted by the Kubo-Greenwood formula. Here, we attempt to solve this problem.

The theory of the intrinsic Hall effect, both linear and nonlinear, is rooted in a geometry which is defined in the Bloch-vector parameter space; the formal expressions are mostly derived from semiclassical concepts. When disorder and interaction are considered, there is no Bloch vector to speak of; one needs a more general quantum geometry, defined in a different parameter space. The nonlinear Hall effect is a fundamental geometric response of the many-body ground state, not a band-structure peculiarity. The higher-level geometrical formulation of the intrinsic Hall effect provides very compact expressions, which have the additional virtue—in the Bloch special case—of yielding the known results in a straightforward way: The logic is not concealed by the algebra.