Layer-confined spin fluctuations and in-plane incommensurate order in the van der Waals magnet -UTe

Sakai, Hironori; Tabata, Chihiro; Kaneko, Koji; Tokiwa, Yoshifumi; Kitazawa, Takafumi; Kambe, Shinsaku; Tokunaga, Yo; Haga, Yoshinori

no journal, , 

-UTe, a van der Waals (vdW) actinide compound, is a narrow-gap semiconductor with moments. We reveal strongly anisotropic, layer-confined spin fluctuations below 20 K, with the -axis component enhanced. Single crystal neutron diffraction finds an incommensurate ordering vector and a longitudinal sinusoidal modulation of -axis moments with AFM stacking along . This behavior can be understood within a crystal-electric-field (CEF) singlet-singlet induced-moment framework.

Spin density wave and van Hove singularity in the kagome metal CeTiBi

Park, P.*; Ortiz, B. R.*; Spargue, M.*; Sakuya, A. P.*; Chen, S. A.*; Frontzek, M. D.*; Tian, W.*; Sibille, R.*; Mazzone, D. G.*; Tabata, Chihiro; et al.

no journal, , 

Heavy fermion states in ionized DNA studied by first-principles calculations

Sekikawa, Takuya; Inokuma, Yusuke; Ono, Yoshiaki*; Tokunaga, Yo; Kai, Takeshi

no journal, , 

Deoxyribonucleic acid (DNA) is recognized as the molecule carrying genetic information in living organisms, but it is also discussed for its potential to exhibit various novel physical properties, including magnetism and superconductivity. In this study, we calculated the structural changes and band dispersion of radiation-irradiated DNA using first-principles electronic structure calculations. We then attempted to reproduce these electronic states using the one-dimensional Kondo lattice model, the most fundamental model for heavy electron systems observed in rare earth compounds. The results show that the electronic states of 11 plus DNA can be reproduced by the one-dimensional Kondo lattice model. This indicates that 11 plus DNA exhibits a heavy electron state, characterized by extremely strong electron-electron interactions causing electrons to behave as if they were heavy. These findings are expected to contribute to the elucidation of DNA's electronic states and the understanding of heavy electron states.

Determination of the hyperfine electron-nuclear level scheme in HoCoZn

Kitazawa, Takafumi; Shimura, Yasuyuki*; Onimaru, Takahiro*; Tsuchida, Shun*; Kubo, Katsunori; Haga, Yoshinori; Sakai, Hironori; Tokiwa, Yoshifumi; Kambe, Shinsaku; Tokunaga, Yo

no journal, , 

We determined the electron-nuclear level scheme in the paramagnetic state of the holmium-based cubic compound HoCoZn using macroscopic thermodynamic probes alone. From magnetization and specific heat measurements, together with detailed analyses, we obtained the crystalline electric field (CEF) parameters, the magnetic exchange constant, and the hyperfine coupling constant between the magnetic moment and the Ho nuclear spin. These refined parameters reveal that the CEF ground state is split by the hyperfine coupling, and that the sextet formed through coupling between the effective spin of the electrons and the spin of the Ho nucleus constitutes the paramagnetic ground state. Remarkably, the splitting energy width exceeds 1 K at zero magnetic field, underscoring the importance of electron-nuclear spin coupling in strongly correlated electron systems.