Pavel A. Volkov, Justin H. Wilson, Kevin P. Lucht, and J. H. Pixley
Phys. Rev. B 107, 174506 (2023) – Published 4 May 2023
Stacking 2D materials with a twist has proven to be a successful strategy to realize exotic phases of electrons. Here, the authors apply these ideas to intrinsic 2D nodal superconductors, showing a similar degree of control over neutral Dirac quasiparticles. Their velocity is quenched close to a “magic” angle, where interactions drive a time-reversal breaking phase transition. Gating and application of current and magnetic fields are shown to allow tuning their dispersion in future experiments and to open topological gaps.
Ilias Efthimiopoulos, Elissaios Stavrou, Koichiro Umemoto, Sathish Mayanna, Antonius Torode, Jesse S. Smith, Stella Chariton, Vitali B. Prakapenka, Alexander F. Goncharov, and Yuejian Wang
Phys. Rev. B 107, 184102 (2023) – Published 4 May 2023
Phys. Rev. B 107, 195404 (2023) – Published 4 May 2023
The authors study the continuum limit of two-dimensional chiral magnets in which the Dzyaloshinskii-Moriya interaction (DMI) is due to the interplay between a smooth magnetic texture and spin-orbit coupling. They investigate corrections to the DMI free energy, in a gradient expansion, and also in the limits of small Rashba spin-orbit coupling or small exchange coupling, revealing non-Lifshitz invariants in higher-order terms. These contributions are significant for filling near the conduction band bottom at strong Rashba spin-orbit coupling and can stabilize nontrivial spin structures.
Peng Li, Huiqing Ye, Yong Hu, Yuan Fang, Zhiguang Xiao, Zhongzheng Wu, Zhaoyang Shan, Ravi P. Singh, Geetha Balakrishnan, Dawei Shen, Yi-feng Yang, Chao Cao, Nicholas C. Plumb, Michael Smidman, Ming Shi, Johann Kroha, Huiqiu Yuan, Frank Steglich, and Yang Liu
Phys. Rev. B 107, L201104 (2023) – Published 4 May 2023
Competition between magnetic order and the Kondo effect is essential for the rich physics of heavy-fermion systems, but its photoemission signature remains elusive. Here, using high-resolution resonant photoemission, the authors reveal that the intensity of the 4 quasiparticle band in CeCoGe exhibits a clear deviation from Kondo-like behavior around the magnetic ordering temperature. The intensity begins to saturate at lower temperatures, coinciding with a change of the magnetic structure. The results demonstrate a distinct scenario for the microscopic coexistence and competition of these phenomena.
