We are pleased to announce that Sarma Kancharla will assume the position of Chief Editor at PRB, effective April 29, 2024.

The researchers here shed new light on the elusive single-particle model of twisted bilayer MoTe${}_2$, a material recently highlighted for hosting fractional Chern insulators at zero magnetic field. By leveraging an advanced machine learning method and density functional theory, the team meticulously maps out the band structure across various twist angles, revealing a pivotal band inversion and refining the theoretical landscape. By enhancing the continuum model with higher harmonic terms, they unveil opposite Chern numbers in the valence bands for key angles, paving the way for predicting diverse Chern states. This comprehensive analysis lays the groundwork for accurately pinpointing correlated phases in this intriguing material, offering a beacon for future explorations.

The observation of fractional Chern insulators in rhombohedral pentalayer graphene twisted on hexagonal boron nitride has initiated a flurry of theoretical work seeking its explanation. As a step towards understanding the origin of these phases, the authors undertake here a first-principles study of the large family of multilayer rhombohedral graphene/boron nitride superlattices, including structural relaxation. The moiré models they obtain faithfully capture the microscopic band structure and are the starting point for understanding the observed topological phases and predicting new ones.

Ensemble density functional theory (EDFT) offers a promising path for computing excitation energies via a theory of the ensemble density — a weighted sum of interacting excited-state densities. Recovering excitation energies is theoretically simple, but practical application requires approximations dependent on weight choice. Here, the authors derive exact conditions for EDFT. Using an exactly solvable model, they illustrate violations of exact conditions, weight-dependent derivative discontinuities in the strong-interaction limit, and ultimately the significance of weight dependence for future functional design.

Using neutron diffraction in pulsed magnetic fields, employing the challenging backscattering geometry, this work establishes the magnetic structure in the spin flop phase of magnetoelectric LiFePO${}_4$ above 32 Tesla. Using pulsed field electric polarization measurements, an unexpectedly complex set of magnetoelectric couplings are found above the critical field. Finally, mean field calculations of the phase diagram demonstrate how access to high field ($H$,$T$) phase diagrams can be complementary to other techniques in pinpointing the spin Hamiltonian

The interactions between conduction electrons and magnetic impurities lead to exotic entangled many-body states. Scanning tunneling microscope allows us to probe many-body excitations of a magnetic impurity and create tunable conduction electron environments by building quantum corrals atom by atom. Combining these techniques, the authors explore here how electronic confinement in quantum corrals affects two types of quantum impurity models, one realizing a candidate system for Kondo physics, and a second realizing a candidate system of spinaron many-body excitations.

Polaritons formed by strong exciton-photon coupling can drastically increase the distance of coherent energy exchange between excitonic materials, but poor durability or low operational temperature in previously demonstrated materials has limited the range of possible applications. Here, the authors demonstrate two-dimensional transition metal dichalcogenide semiconductors placed in a tunable optical microcavity as a durable, room-temperature platform for polariton-mediated energy transfer between excitons. The full quantum mechanical simulations based on experimental parameters reveal efficient energy transfer over 1 μm distance on a femtosecond timescale.

To be, or not to be, phonon mediated. That is the first question to answer for new superconductors, especially if they show important analogies with the cuprates. Here, the infinite-layer nickelates are scrutinized by means of first-principles calculations, including dynamical correlations in the GW approximation. The results suggest phonon-mediated superconductivity with low-$T_c$ in the parent compounds. However, the analysis of doping and pressure confirm the non-phonon mediated nature of the mechanism behind the maximal $T_c$ observed in these systems.

Nodal-ring semimetals have attracted attention for their unique band topology and resulting nontrivial quantum phenomena. Using fermiology under high pressure, the authors reveal here a pure nodal-ring semimetal state in pressurized black phosphorus. Semimetallic black phosphorus can provide an ideal platform to explore the true nature of this topological quantum state using external pressure as an effective tuning parameter.

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.

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.

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.

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.

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.

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.

Physical Review B is proud to announce the creation of an Early Career Researcher Advisory Board (ECAB). The 18 inaugural members are listed on the PRB Editorial Team page. We thank them for agreeing to serve. They will act as a focus group and provide advice from their perspective on how PRB can best serve the needs of early career researchers and maintain its important role in condensed matter and materials physics going into the future. The new board members are based in 10 different countries. Stephen Nagler, PRB Lead Editor, will chair the board.

PRB Editorial Team page

APS has selected 156 Outstanding Referees for 2024 who have demonstrated exceptional work in the assessment of manuscripts published in the Physical Review journals. A full list of the Outstanding Referees is available online.