EDITORS' SUGGESTION
This study explores a novel approach to exciting spin waves in single-crystal iron using parametric pumping. This technique achieves significant results at exceptionally low power levels, revealing unconventional behavior in this material. These findings suggest that single-crystal iron holds immense promise as a platform for spin-wave manipulation. A systematic investigation of parametric pumping in single-crystal iron paves the way for the development of low-power spin-wave devices.
Shoki Nezu, Thomas Scheike, Hiroaki Sukegawa, and Koji Sekiguchi
Phys. Rev. B 109, 184402 (2024)
EDITORS' SUGGESTION
The rare-earth titanate perovskites exhibit a rich interplay among spin, orbital and structural degrees of freedom. Here, electron spin resonance and nuclear magnetic resonance are combined to study the low-energy spin properties of a series of rare-earth titanates. The measurements reveal slow spin fluctuations at temperatures far above the ferromagnetic transition, as well as a low-lying electronic excited state that likely plays a pivotal role in the formation of magnetic order.
A. Najev et al.
Phys. Rev. B 109, 174406 (2024)
EDITORS' SUGGESTION
Molecular vibrations play a key role in sensing, catalysis, molecular electronics and beyond, but investigating the coherence and dynamics of individual molecules is extremely challenging. Here, the authors study the vibrational dynamics of ~100 molecules confined in plasmonic nanocavities through simultaneous coherent and incoherent Raman scattering to access both phonon population decay and dephasing. The results show that the dephasing of collective molecular vibrations is accelerated by excitation-power-dependent processes, amplified by the plasmonic near-field enhancement in the cavity.
Lukas A. Jakob et al.
Phys. Rev. B 109, 195404 (2024)
EDITORS' SUGGESTION
In systems of fermions at finite temperatures, interactions are believed to induce a crossover from the coherent and ballistic streaming of quasiparticles at early times, to incoherent diffusive behavior at late times. Here, the authors develop a numerical method to simulate such systems. They use the method to determine how the rate of diffusion depends on the strength of interactions, and to confirm the predicted crossover.
Jerome Lloyd, Tibor Rakovszky, Frank Pollmann, and Curt von Keyserlingk
Phys. Rev. B 109, 205108 (2024)
EDITORS' SUGGESTION
This paper delves into the intriguing connection between electronic topology and the two-dimensional melting of solids. Conventionally, Kosterlitz-Thouless-Halperin-Nelson-Young theory shows that the behavior of disclinations determines the melting process of 2D crystals. By uncovering how electrons become trapped in disclinations due to nontrivial electronic topology, the authors shed light here on a deviation of the disclination-involving melting process, because of the increase in the energy barrier for unbinding disclination pairs.
Junyan Ma and H. Huang
Phys. Rev. B 109, 205107 (2024)
EDITORS' SUGGESTION
This paper introduces scalar measures that adequately characterize the non-Hermitian skin effects under open boundary condition. Using these measures, the authors reveal that the topological properties of the non-Hermitian skin effect give a macroscopic enhancement of non-normality under open boundary condition. The topological enhancement of non-normality governs the perturbation sensitivity of the spectra and the anomalous time-evolution dynamics intrinsic to non-Hermiticity. They also show that these measures correctly describe the disorder-induced topological phase transitions of the skin effect.
Yusuke O. Nakai et al.
Phys. Rev. B 109, 144203 (2024)
EDITORS' SUGGESTION
Solid-state quantum emitters often suffer from temporal variations of their transition energies, inherited from fluctuations in the host crystal environment. This spectral diffusion (SD) is detrimental to the emitter linewidth but is often challenging to characterize experimentally. The authors show here that, under resonant laser excitation, the statistics of the scattered photons offer multiple signatures of the SD process, making it possible to discriminate between discrete jumps and continuous diffusion, as well as to access relevant parameters of the SD mechanisms.
Aymeric Delteil, Stéphanie Buil, and Jean-Pierre Hermier
Phys. Rev. B 109, 155308 (2024)
EDITORS' SUGGESTION
This work establishes a direct connection between the magic-angle effect, originally discovered in two-dimensional twisted bilayer graphene, and the avoided quantum critical point in disordered three-dimensional Weyl and Dirac semimetals. This is achieved through a theoretical study of the interplay of quasiperiodicity and disorder in a model for three-dimensional inversion broken Weyl semimetal. The predictions can be tested in future ultracold atom or circuit quantum electrodynamic experiments.
J. H. Pixley, David A. Huse, and Justin H. Wilson
Phys. Rev. B 109, 165151 (2024)
EDITORS' SUGGESTION
By exploiting naturally occurring charge islands due to twist angle variations in twisted bilayer graphene, the authors measure here how strongly charge carriers interact. They discover negative capacitance contributions, which are indicative of correlation effects near band insulators at full filling on both flat and remote sides, and at integer partial fillings. The correlation strength remains constant across all bands, unaffected by a magnetic field. The reported results point to a possible Wigner crystal phase as the underlying mechanism.
Robin J. Dolleman et al.
Phys. Rev. B 109, 155430 (2024)
EDITORS' SUGGESTION
Using a combination of neutron powder diffraction and SQUID magnetometry, this work explores the impact that hydrogen (deuterium) incorporation has on the magnetic properties of NdGaD (=0, 0.9, and 1.6). The experimental results show that hydrogenation leads to large change in the magnetic order and to a significant decrease in the corresponding transition temperatures. Furthermore, the results suggest that this is related to changes in the electronic structure and the Nd-Nd distances induced by the hydrogenation.
Johan Cedervall et al.
Phys. Rev. B 109, 134434 (2024)
EDITORS' SUGGESTION
Chiral phonons are lattice vibration modes in which the atomic circular motions produce nonzero angular momentum. In monolayer MoS, the authors demonstrate here a chiral phonon mode at ~270 cm that is activated by resonant excitation of the bright exciton. Under an out-of-plane magnetic field, this mode exhibits large Zeeman splitting, which corresponds to an effective magnetic moment of ~2.5 μ. This study will stimulate research on the effective magnetic moments that emerge from the interplay between chiral phonons and the valley degree of freedom.
Chunli Tang et al.
Phys. Rev. B 109, 155426 (2024)
EDITORS' SUGGESTION
Topologically trivial insulators can further be identified as obstructed atomic insulators when the symmetric Wannier functions are centered at positions not occupied by atoms. Here, the authors derive all charge-filling criteria that force a topologically trivial insulator to an obstructed atomic insulator. About one thousand filling-enforced obstructed atomic insulators are found through high-throughput calculations.
Yuanfeng Xu et al.
Phys. Rev. B 109, 165139 (2024)
EDITORS' SUGGESTION
Antimony telluride (SbTe) has garnered significant attention within the condensed matter community, particularly as one of the earliest experimentally recognized topological insulators. However, despite substantial investigation, our understanding of the bulk electronic band structure of SbTe remains incomplete. Here, the authors employ a comprehensive experimental and theoretical approach integrating magneto-optical, optical, magnetotransport and techniques to examine SbTe. Their findings reveal that this material possesses a direct energy band gap at the center of the Brillouin zone, while also exhibiting additional low-energy band extrema in mirror planes.
I. Mohelsky et al.
Phys. Rev. B 109, 165205 (2024)
EDITORS' SUGGESTION
The so-called Remeika phase of the 3–4–13 class of materials is a candidate system for investigating topological electronic phenomena. The authors explore here an antiferromagnetic ordered structure comprising one-dimensional Nd chains connected via the triangular lattice in NdRhSn, which is superimposed on the chiral structure like that in several Remeika phase compounds. The results suggest that simultaneously broken spatial and time-reversal symmetries in this material open an avenue to investigate magnetic interactions mediated by the topological electrons protected by the noncentrosymmetric chiral structure.
Ami Shimoda et al.
Phys. Rev. B 109, 134425 (2024)