18 citations · 57 across the 11 of their papers we have counts for
8 papers · 1 filter
Riemannian geometric classification and emergent phenomena of magnetic textures
Koki Shinada, Naoto Nagaosa
We propose a new classification of magnetic textures from the viewpoint of differential geometry. Magnetic textures are conventionally classified into collinear, coplanar, and nonc…
Quantum geometric bounds for observables: Linear responses, Drude weight, and orbital magnetization
Koki Shinada, Naoto Nagaosa
The quantum geometric tensor (QGT) provides nontrivial bounds among physical quantities, as exemplified by the metric-curvature inequality. In this paper, we investigate various bo…
Thermodynamic formulation of the spin magnetic octupole moment in bulk crystals
Jun Ōiké, Robert Peters, Koki Shinada
The discovery of unconventional antiferromagnets, such as altermagnets, has drawn significant attention to higher-rank magnetic multipoles, particularly magnetic octupoles. Despite…
Nonlinear Magnetoelectric Effect under Magnetic Octupole Order: Its Application to a -Wave Altermagnet and a Pyrochlore Lattice with All-In/All-Out Magnetic Order
Jun Ōiké, Koki Shinada, Robert Peters
Extensive investigation has recently been conducted into a new class of antiferromagnetic order known as magnetic octupole order. However, the high rank of octupoles makes it diffi…
Orbital optical activity in noncentrosymmetric metals and superconductors
Koki Shinada, Robert Peters
We present the optical activity induced by the orbital magnetic moment in metals and superconductors using Green's function formalization. We show that an apparent singularity of t…
Unique properties of the optical activity in noncentrosymmetric superconductors: sum rule, missing area, and relation with the superconducting Edelstein effect
Koki Shinada, Robert Peters
We present general properties of the optical activity in noncentrosymmetric materials, including superconductors. We derive a sum rule of the optical activity in general electric s…
Quantum theory of the Intrinsic Orbital Magnetoelectric Effect in itinerant electron systems at finite temperatures
Koki Shinada, Akira Kofuji, Robert Peters
Magnetization can be induced by an electric field in systems without inversion symmetry and time-reversal symmetry . This phenomenon is called the magnet…
Orbital Gravito-Magnetoelectric response and Orbital magnetic quadrupole moment correction
Koki Shinada, Robert Peters
The magnetoelectric effect has been actively studied in multiferroics since the first observation in an antiferromagnetic, . This effect appears in systems withou…