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.

Antimony telluride (Sb${}_2$Te${}_3$) 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 Sb${}_2$Te${}_3$ remains incomplete. Here, the authors employ a comprehensive experimental and theoretical approach integrating magneto-optical, optical, magnetotransport and $ab$ $initio$ techniques to examine Sb${}_2$Te${}_3$. 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.

Altermagnetism is increasingly gaining attention and RuO${}_2$ thin films have been arguably the most popular altermagnetic candidate. However, most publications miss a disturbing fact: direct experiments indicate the absence of any sizable ordered magnetism in stoichiometric bulk samples. Here, the authors confirm, through first-principles calculations, that the bulk samples are indeed far from ordered magnetism, but intrinsic hole doping strongly enhances the tendency to magnetism, suggesting an interesting possibility that the measured thin films may be magnetically different from stoichiometric bulk RuO${}_2$.

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 Nd${}_3$Rh${}_4$Sn${}_{13}$, 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.

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.

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To be useful for quantum computation, qubits in an array must remain localized – that is, not “dressed” too much by nearby degrees of freedom. This localization has been previously achieved using disorder. But the authors observe here that a more effective route to localization is with a quasiperiodic patterning of the qubit array Hamiltonian. This paper develops two different perturbation approaches to calculate diagnostics for many-body localization in quasiperiodic superconducting transmon arrays. Perturbing in anharmonicity versus perturbing in hopping strength give complementary information.

Charge density waves (CDW) accompanied by superconductivity (SC) is an enduring topic in the field of condensed matter physics for it involves exotic physical properties and quantum states. This paper presents a competitive relationship between the anisotropic SC and CDW down to the two-dimensional limit in ZrTe${}_3$, a quasi-one-dimensional material. It reveals an unusual nonmonotonic evolution versus thickness and suggests a complicated superconducting mechanism in this compound.

By examining the complex interactions between light and magnetism, this work uncovers the dominant role played by light’s spin angular momentum in magnetic all-optical switching (AOS) using Co/Pt ferromagnetic thin films. The authors use femtosecond vortex beams to demonstrate that the topological charge and orbital angular momentum’s handedness are inconsequential. As a result, this research enhances our comprehension and underscores the pivotal correlation between the angular momentum of light and magnetization dynamics.

Strong disorder in many-body quantum systems leads to many-body localization (MBL), manifested as long-time memory of the initial state. Spatial regions of anomalously weak disorder, arising due to fluctuations in the disordered potential, may act as ergodic inclusions that seed quantum avalanches and destabilize the MBL. To investigate this mechanism in a controlled setting, the authors plant ergodic inclusions by engineering regions of a weak disorder and compare the system’s time evolution with predictions of the avalanche theory.

The tetragonal 122 family of compounds exhibits a wide variety of intriguing phenomena, many of which are intimately related to their magnetic properties. Here, the magnetic phase diagrams of DyRh${}_2$Si${}_2$ and HoRh${}_2$Si${}_2$ are explored in detail by extremely sensitive thermal expansion and magnetostriction measurements. Some similarities can be attributed to comparable crystalline electric fields in these compounds, while an additional transition is revealed for HoRh${}_2$Si${}_2$ just below the Néel temperature ($T_N$) and analyzed via the magnetic Grüneisen ratio.

High-order harmonics and the reverse of the squaring-up process is uncovered in the evolution of magnetic orders of the centrosymmetric layered triangular-lattice magnet HoPdAl${}_4$Ge${}_2$. Ho${}^{3+}$ spins order antiferromagnetically as a transverse spin density wave below 10.5 K. Upon further cooling through 5.5 K, the high-order harmonics develop, suggesting a “squaring up” process. It is surprising that the squaring up process does not continue down to 0 K but reverses the trend below ~3 K or by applying a small magnetic field.

The superfluid stiffness $D_s$($T$) is one of the key characteristics of a superconductor, determining the magnetic penetration length and, in two dimensions, the critical temperature. For Galilean invariant systems, it is known that the zero-temperature stiffness takes a universal value $D_s^{Gal}$ = $\frac{n}{m}$ ($T$=0), while for non-Galilean invariant systems the superfluid stiffness may be suppressed. Here, the authors demonstrate when and how vertex corrections may cancel suppression of the superfluid stiffness at strong coupling.

Although many other transition metal halides have been magnetically characterized, CrI${}_2$, a proposed “sliding ferroelectric”, has been overlooked. Via neutron powder diffraction, the authors report here that a screw-like helimagnetic order develops below 17 K, corresponding to a ~90º spin rotation per Cr ion along the “ribbon chains”. Calculations suggest that, as in the structurally and magnetically similar copper dihalides, the helimagnetism arises due to a sufficiently antiferromagnetic intrachain next-nearest-neighbor coupling.

$\alpha$-RuCl${}_3$ is a candidate for realizing the Kitaev quantum spin liquid state. Despite extensive research efforts, its crystal structure at temperatures relevant to studying Kitaev physics has been controversial. Here, the authors examine a single crystal with minimal twinning and stacking faults, allowing them to unambiguously determine the symmetry change across the structural phase transition. They find that the three-fold rotational symmetry of the honeycomb plane is restored in the low-temperature phase with symmetry group $R\overline{3}$, although this symmetry is explicitly broken in the room-temperature $C2/m$ structure.

Rare-earth tritellurides are van der Waals antiferromagnets that are a promising platform not only for spintronic devices but also for the study of the correlation between the charge density wave (CDW) and magnetic states in low-dimensional materials. Here, the authors perform longitudinal and Hall resistivity measurements in exfoliated $R$Te${}_3$ ($R$=La, Ce, Tb) thin film devices. The carrier mobility and concentration change at the magnetic transition temperature. The result suggests the strong coupling between the CDW and antiferromagnetic phases.

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