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

The authors explore critical properties of entanglement phase transitions in random tensor networks and monitored quantum circuits with Clifford tensors/gates for on-site Hilbert space dimensions which are powers of a prime number $p$. Exact mappings to replica spin models and characterizations of their symmetry groups predict that all universal properties will depend only on $p$. These predictions are confirmed with extensive numerical simulations. The authors also establish multifractal scaling of the purity, reflected in a continuous spectrum of critical exponents, while the typical exponent is the prefactor of the logarithm in the entanglement entropy.

Ultrahigh-mobility two-dimensional electron gases show an astonishing robust negative magnetoresistance at zero magnetic field. $In$ $situ$ variation of the electron density enables a deep insight into the nature of this negative magnetoresistance. Here, the authors investigate the temperature-dependent giant negative magnetoresistance (GNMR) as a function of the electron density for several temperatures and currents. They find that the GNMR behavior depends decisively on the electron density. This observation is attributed to a changed disorder potential with electron density.

Here, the authors report on the superconducting properties of the ternary noncentrosymmetric superconductor Re${}_8$NbTa, a new member of the Re-based superconductors that are known for the frequent occurrence of time-reversal symmetry breaking and their complex superconducting ground states. Bulk and transverse field muon spin rotation/relaxation (μSR) measurements confirm moderately coupled, fully gapped superconductivity. However, zero-field μSR measurements indicate the possible presence of spin fluctuation/time-reversal symmetry breaking in the superconducting ground state, suggesting the unconventional superconductivity in Re${}_8$NbTa.

Conformal field theory (CFT) has played a pivotal role in understanding the topological phases of matter represented by many fractional quantum Hall effect (FQHE) trial wave functions. Previous papers have shown how the topological properties of a trial wave function expressible as a CFT correlation function can be related to properties of the corresponding CFT, assuming a field-theoretic generalization of Laughlin’s plasma analogy holds. Here, the authors show how these methods can be extended to understand certain topological properties of parton-type FQHE trial wave functions.

Using x-ray resonant magnetic scattering in vector magnetic fields, this work explores the effect of the anisotropic exchange interaction on the magnetic spiral pitch in the cubic chiral magnet Co${}_8$Zn${}_8$Mn${}_4$. The experimental data reveal up to a 5% variation in the helical pitch within the (001) plane depending on temperature. Furthermore, the results reveal the existence of intrinsic competition between magnetocrystalline and exchange anisotropies in this material, with each favoring different orientations of the helical vector in the ground state.

In contrast to dipolar refrigerator magnets, multipolar magnets possess more than just a north pole and a south pole. Using first principles and exact diagonalization calculations, this work establishes transition metal based vacancy-ordered halide double perovskites as new candidates for octupolar magnetism. The authors uncover a non-Kramers doublet ground state in these materials, explain the strong temperature-dependent effective magnetic moment, highlight the breakdown of the classic Kotani plot, and predict hidden octupolar order which may be tested in future experiments.

In hybrid-improper ferroelectrics, two nonpolar structural distortions jointly give rise to a spontaneous electric polarization. In Ca${}_3$Mn${}_{1.9}$Ti${}_{0.1}$O${}_7$, this ferroelectric state coexists with antiferromagnetism to yield a new type of multiferroic. Here, the authors show that it is characterized by a pronounced magnetoelectric response of the ferroelectric state to the intrinsic magnetic ordering and to external magnetic fields. Optical second harmonic generation is of particular advantage to this study, as it provides access to the electric polarization with spatial resolution of its domains.

Here, the authors make a fundamental theoretical advancement by unifying the theory of optical transitions in semiconductors including direct and phonon-assisted processes. This unification overcomes the fundamental limitation in the textbook theory of phonon-assisted optical absorption that gives unphysical absorption rates for photon energies greater than the direct band gap. They demonstrate the predictive power of their theory by calculating optical absorption and luminescence in standard semiconductors, and they achieve excellent quantitative agreement with the best available experiments. This work brings a paradigm shift in the theory of optical transitions, and opens the pathway for precise calculations of semiconductor optical properties.

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.

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.

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.