This is were we announce new journal articles and conference proceedings published by members of the group.
Superconducting (SC) state has spin and orbital degrees of freedom, and spin-triplet superconductivity shows multiple SC phases because of the presence of these degrees of freedom. However, the observation of spin-direction rotation occurring inside the SC state (SC spin rotation) has hardly been reported. Uranium ditelluride, a recently found topological superconductor, exhibits various SC phases […]
The emergence of charge-neutral fermionic excitations in magnetic systems is one of the unresolved issues in recent condensed matter physics. This type of excitations has been observed in various systems, such as low-dimensional quantum spin liquids, Kondo insulators, and antiferromagnetic insulators. Here, we report the presence of a pronounced gapless spin excitation in the low-temperature […]
Recently, a superconducting (SC) transition from low-field (LF) to high-field (HF) SC states was reported in CeRh2As2, indicating the existence of multiple SC states. It has been theoretically noted that the existence of two Ce sites in the unit cell, the so-called sub-lattice degrees of freedom owing to the local inversion symmetry breaking at the […]
Translational symmetry breaking in fluid is antagonistic but can be realized insuperconductivity, which is quantum-mechanical coherent fluid formed byelectron pairs. This novel superconducting state, known as the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, can be induced by time-reversal-symmetrybreaking magnetic field applied to spin-singlet superconductors. This stateintrinsically causes the superconducting spin smecticity, spin-density-modulatedfluidity with spontaneous translational-symmetry breaking. Detection of […]
To investigate the normal-state magnetic properties of UTe 2 under pressure, weperform 125 Te nuclear magnetic resonance (NMR) measurements up to 2 GPa.Below 1.2 GPa, the b -axis NMR Knight shift shows a broad maximum at the so-called T χ max on cooling, which is consistent with the magnetizationmeasurement under pressure. T χ max decreases […]
In the Mott insulator Ca2RuO4, which is a strongly correlated material material, we observed for the first time the generation of high-order harmonics that convert a strong infrared laser beam into visible light. Our experiments show that the intensity of the generated signal follows a surprisingly simple rule. In recent years, with the development of ultrashort […]
Spatial inversion symmetry in crystal structures is closely related to the superconducting (SC) and magnetic properties of materials. Recently, several theoretical proposals that predict various interesting phenomena caused by the breaking of the local inversion symmetry have been presented. However, experimental validation has not yet progressed owing to the lack of model materials. Here we […]
The mechanism of unconventional superconductivity, such as high-temperature-cuprate, Fe-based, and heavy-fermion superconductors, has been studied as a central issue in condensed-matter physics. Spin fluctuations, instead of phonons, are considered to be responsible for the formation of Cooper pairs, and many efforts have been made to confirm this mechanism experimentally. Although a qualitative consensus seems to […]
Investigating the pressure dependence of the superconducting (SC) transition temperature Tc is crucial for understanding the SC mechanism. Herein, we report on the pressure dependence of Tc in the nonmagnetic topological line-nodal material CaSb2, based on measurements of electric resistance and alternating current magnetic susceptibility. Tc initially increases with increasing pressure and peaks at ∼ […]
CaSb2 has a crystal structure with a special arrangement called “non-symmorphic’’. Due to this structure, it is expected that the bulk electronic energy bands have four-fold degeneracy along a line in the momentum space, which is called Dirac line node. In 2020, we discovered that CaSb2 exhibits superconductivity. Much attention has been paid to the […]