Related papers: Magnon gravitomagnetoelectric effect in noncentros…
We revisit a quantum-mechanical formula of the spin magnetic quadrupole moment (MQM) in periodic crystals. Two previous attempts were inconsistent with each other; one is gauge dependent, and the other is gauge invariant. Here we define the…
We derive a quantum-mechanical formula of the orbital magnetic quadrupole moment (MQM) in periodic systems by using the gauge-covariant gradient expansion. This formula is valid for insulators and metals at zero and finite temperature. We…
The magnetoelectric effect has been actively studied in multiferroics since the first observation in an antiferromagnetic, $\mathrm{Cr_2O_3}$. This effect appears in systems without spatial inversion symmetry and time-reversal symmetry and…
We investigate the nonequilibrium spin polarization due to a temperature gradient in antiferromagnetic insulators, which is the magnonic analogue of the inverse spin-galvanic effect of electrons. We derive a linear response theory of a…
Our magnetic, electrical, and thermal measurements on single-crystals of the novel Mott insulator, Sr2IrO4, reveal a novel giant magneto-electric effect (GME) arising from a frustrated magnetic/ferroelectric state whose signatures are: (1)…
Magnetization can be induced by an electric field in systems without inversion symmetry $\mathcal{P}$ and time-reversal symmetry $\mathcal{T}$. This phenomenon is called the magnetoelectric (ME) effect. The spin ME effect has been actively…
Our joint theoretical and computer experimental study of heat-to-spin conversion reveals that noncollinear antiferromagnetic insulators are promising materials for generating magnon spin currents upon application of a temperature gradient:…
Quantized spin waves, or magnons, in a magnetic insulator are assumed to interact weakly with the surroundings, and to flow with little dissipation or drag, producing exceptionally long diffusion lengths and relaxation times. In analogy to…
The design of spin-transport based devices such as magnon transistors or spin valves will require multilayer systems composed of different magnetic materials with different physical properties. Such layered structures can show various…
One of the hallmarks of time-reversal-symmetric topological insulators in three dimensions is the topological magnetoelectric effect (TME). So far, a time-reversal breaking variant of this effect has attracted much attention, in the sense…
We investigate the effect of magnon-magnon interactions on the dispersion and polarization of magnons in collinear antiferromagnetic (AF) insulators at finite temperatures. In two-sublattice AF systems with either uniaxial or biaxial…
We predict that a temperature gradient can induce a magnon-mediated spin Hall response in an antiferromagnet with non-trivial magnon Berry curvature. We develop a linear response theory which gives a general condition for a Hall current to…
Magnon excitations in antiferromagnetic materials and their physical implications enable novel device concepts not available in ferromagnets, emerging as a new area of active research. A unique characteristic of antiferromagnetic magnons is…
It is a highly nontrivial question whether a magnetization can be induced by applying a nonlinear temperature gradient in the absence of any linear component. In this work, we address this issue and provide explicit examples demonstrating…
The ferromagnet-topological insulator-ferromagnet (FM-TI-FM) junction exhibits thermal and electrical quantum Hall effects. The generated Hall voltage and transverse temperature gradient can be controlled by the directions of magnetizations…
Multiferroic materials have undergone extensive research in the past two decades in an effort to produce a sizable room-temperature magneto-electric (ME) effect in either exclusive or composite materials for use in a variety of electronic…
Recent experiments have established a qualitative difference between the magnetization temperature-dependences $M(T)$ of quantum Hall ferromagnets at integer and fractional filling factors. We explain this difference in terms of the…
The influence of an asymmetric in-plane magnetic anisotropy on the thermally activated spin current is studied theoretically for two different systems; (i) the system consisting of a ferromagnetic insulator in a direct contact with a…
Antiferromagnets (AFMs) are presently considered as promising materials for applications in spintronics and random access memories due to the robustness of information stored in AFM state against perturbing magnetic fields (P. Wadley et…
We demonstrate theoretically that the thermal Hall effect of magnons in collinear antiferromagnetic insulators is an indicator of magnetic and topological phase transitions in the magnon spectrum. The transversal heat current of magnons…