Spin-orbit interaction has established itself as a key player in the emergent phenomena in modern... more Spin-orbit interaction has established itself as a key player in the emergent phenomena in modern condensed matter, including topological insulator, spin liquid and spin-dependent transports. However, its function is rather limited to adding topological nature to band kinetics, leaving behind the growing interest in the direct interplay with electron correlation. Here, we prove by our spinor line graph theory that a very strong spin-orbit interaction realized in 5d pyrochlore electronic systems generates multiply degenerate perfect flat bands. Unlike any of the previous flat bands, the electrons in this band localize in real space by destructively interfering with each other in a spin selective manner governed by the SU(2) gauge field. These electrons avoid the Coulomb interaction by self-organizing their localized wave functions, which may lead to a flat-band state with a stiff spin chirality. It also causes perfectly trimerized charge ordering, which may explain the recently disco...
Spin-orbit interaction established itself as a major role player for emergent phenomena in modern... more Spin-orbit interaction established itself as a major role player for emergent phenomena in modern condensed matter including a topological insulator, spin liquid and spin-dependent transports. However, its function is rather limited to adding topological nature to each phases of matter. We prove by our spinor line graph theory that a very strong spin-orbit interaction realized in 5d pyrochlore electronic systems generates multiply degenerate perfect flat bands. Unlike any of the previous flat bands, the electrons living there localize in real space by destructively interfering with each other in a spin selective manner ruled by the SU(2) gauge field. These electrons avoid the Coulomb interaction by self-organizing their localized wave functions. This gives rise to the trimerized charge ordering hand in hand with a stiff spin chirality, which may explain the recently found exotic low-temperature insulating phase of CsW2O6.
We perform magnetic susceptibility and magnetic torque measurements on the organic κ-(BEDT-TTF)2H... more We perform magnetic susceptibility and magnetic torque measurements on the organic κ-(BEDT-TTF)2Hg(SCN)2Br, which is recently suggested to host an exotic quantum dipole-liquid in its low-temperature insulating phase. Below the metal-insulator (MI) transition temperature, the magnetic susceptibility follows a Curie–Weiss law with a positive Curie–Weiss temperature, and a particular $$M\propto \sqrt{H}$$ M ∝ H curve is observed. The emergent ferromagnetically interacting spins amount to about 1/6 of the full spin moment of localized charges. Taking account of the possible inhomogeneous quasi-charge-order that forms a dipole-liquid, we construct a model of antiferromagnetically interacting spin chains in two adjacent charge-ordered domains, which are coupled via fluctuating charges on a Mott-dimer at the boundary. We find that the charge fluctuations can draw a weak ferromagnetic moment out of the spin singlet domains.
One of the major strategies to control magnetism in spintronics is to utilize the coupling betwee... more One of the major strategies to control magnetism in spintronics is to utilize the coupling between electron spin and its orbital motion. The Rashba and Dresselhaus spin–orbit couplings induce magnetic textures of band electrons called spin momentum locking, which produces a spin torque by the injection of electric current. However, joule heating had been a bottleneck for device applications. Here, we propose a theory to generate further rich spin textures in insulating antiferromagnets with broken spatial inversion symmetry (SIS), which is easily controlled by a small magnetic field. In antiferromagnets, the ordered moments host two species of magnons that serve as internal degrees of freedom in analogy with electron spins. The Dzyaloshinskii–Moriya interaction introduced by the SIS breaking couples the two-magnon-degrees of freedom with the magnon momentum. We present a systematic way to design such texture and to detect it via magnonic spin current for the realization of antiferro...
Spin-orbit interaction has established itself as a key player in the emergent phenomena in modern... more Spin-orbit interaction has established itself as a key player in the emergent phenomena in modern condensed matter, including topological insulator, spin liquid and spin-dependent transports. However, its function is rather limited to adding topological nature to band kinetics, leaving behind the growing interest in the direct interplay with electron correlation. Here, we prove by our spinor line graph theory that a very strong spin-orbit interaction realized in 5d pyrochlore electronic systems generates multiply degenerate perfect flat bands. Unlike any of the previous flat bands, the electrons in this band localize in real space by destructively interfering with each other in a spin selective manner governed by the SU(2) gauge field. These electrons avoid the Coulomb interaction by self-organizing their localized wave functions, which may lead to a flat-band state with a stiff spin chirality. It also causes perfectly trimerized charge ordering, which may explain the recently disco...
Spin-orbit interaction established itself as a major role player for emergent phenomena in modern... more Spin-orbit interaction established itself as a major role player for emergent phenomena in modern condensed matter including a topological insulator, spin liquid and spin-dependent transports. However, its function is rather limited to adding topological nature to each phases of matter. We prove by our spinor line graph theory that a very strong spin-orbit interaction realized in 5d pyrochlore electronic systems generates multiply degenerate perfect flat bands. Unlike any of the previous flat bands, the electrons living there localize in real space by destructively interfering with each other in a spin selective manner ruled by the SU(2) gauge field. These electrons avoid the Coulomb interaction by self-organizing their localized wave functions. This gives rise to the trimerized charge ordering hand in hand with a stiff spin chirality, which may explain the recently found exotic low-temperature insulating phase of CsW2O6.
We perform magnetic susceptibility and magnetic torque measurements on the organic κ-(BEDT-TTF)2H... more We perform magnetic susceptibility and magnetic torque measurements on the organic κ-(BEDT-TTF)2Hg(SCN)2Br, which is recently suggested to host an exotic quantum dipole-liquid in its low-temperature insulating phase. Below the metal-insulator (MI) transition temperature, the magnetic susceptibility follows a Curie–Weiss law with a positive Curie–Weiss temperature, and a particular $$M\propto \sqrt{H}$$ M ∝ H curve is observed. The emergent ferromagnetically interacting spins amount to about 1/6 of the full spin moment of localized charges. Taking account of the possible inhomogeneous quasi-charge-order that forms a dipole-liquid, we construct a model of antiferromagnetically interacting spin chains in two adjacent charge-ordered domains, which are coupled via fluctuating charges on a Mott-dimer at the boundary. We find that the charge fluctuations can draw a weak ferromagnetic moment out of the spin singlet domains.
One of the major strategies to control magnetism in spintronics is to utilize the coupling betwee... more One of the major strategies to control magnetism in spintronics is to utilize the coupling between electron spin and its orbital motion. The Rashba and Dresselhaus spin–orbit couplings induce magnetic textures of band electrons called spin momentum locking, which produces a spin torque by the injection of electric current. However, joule heating had been a bottleneck for device applications. Here, we propose a theory to generate further rich spin textures in insulating antiferromagnets with broken spatial inversion symmetry (SIS), which is easily controlled by a small magnetic field. In antiferromagnets, the ordered moments host two species of magnons that serve as internal degrees of freedom in analogy with electron spins. The Dzyaloshinskii–Moriya interaction introduced by the SIS breaking couples the two-magnon-degrees of freedom with the magnon momentum. We present a systematic way to design such texture and to detect it via magnonic spin current for the realization of antiferro...
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Papers by chisa hotta