| Volume 108, Issues 1 - 4 July 2023 | | Advertisement  | The first published articles from PRX Life, APS's new interdisciplinary, open-access journal exclusively for quantitative biological research, are now online. Access highly selective research at the intersection of physics and biology every month by signing up for alerts. | | | | | |
Advertisement | Get to know the candidates for Vice President, General Councilor, International Councilor, and Chair-Elect of the Nominating Committee. Polls are currently open, and will close August 25. Learn more. | | | | | Advertisement | 2024 Committee Nominations are currently open, and will close August 4. Please nominate colleagues (or yourself). Service by APS's diverse, talented, and engaged membership strengthens our community and enhances the leadership skills of committee members. | | | | | | Not an APS member? Join today to start connecting with a community of more than 50,000 physicists. | | | | Editors' Suggestion Petter Rosander, Erik Fransson, Cosme Milesi-Brault, Constance Toulouse, Frédéric Bourdarot, Andrea Piovano, Alexei Bossak, Mael Guennou, and Göran Wahnström Phys. Rev. B 108, 014309 (2023) – Published 25 July 2023  | BaZrO3 is one of the very few perovskites that is claimed to remain cubic down to 0 K, but its tendency towards an antiferrodistortive (AFD) instability has fueled a lot of debates. Here, the AFD phonon mode is studied using inelastic neutron scattering (INS) and inelastic x-ray scattering (IXS), combined with a computational approach including anharmonicity. Both classical molecular dynamics (MD) and a self-consistent phonon approach are used, the latter including quantum fluctuations of the atomic motion. This robust description of the AFD mode clarifies that BaZrO3 stays cubic down to 0 K. | | | | | | Editors' Suggestion A. Elghandour, L. Gries, L. Singer, M. Hoffmann, S. Spachmann, M. Uhlarz, K. Dey, and R. Klingeler Phys. Rev. B 108, 014406 (2023) – Published 5 July 2023  | Magnetic anisotropy describes the tendency of a material to exhibit different magnetic behavior along different crystallographic directions. Here, the authors mix two antiferromagnets, namely MnTiO3 and NiTiO3, to form Ni0.25Mn0.75TiO3. The parent magnets are of competing anisotropy. The former has an easy magnetic axis along the c axis, whereas the latter has an easy magnetic plane within the ab plane. The authors also shed light on the doping effect upon the long-range magnetic order, emergent magnetic phases, and the magnetic entropy consumption in comparison to the parent magnets. Finally, they employ different thermodynamic probes to build a complex and rich anisotropic magnetic phase diagram of Ni0.25Mn0.75TiO3. | | | | | | Editors' Suggestion Carmen Martín Valderrama, Mikel Quintana, and Andreas Berger Phys. Rev. B 108, 014415 (2023) – Published 12 July 2023  | The magneto-optical Kerr effect (MOKE) is described by a dielectric tensor ϵ that contains magnetization dependent terms, whose impact on reflected light is solved as an electromagnetic boundary problem. Corresponding solutions for the Jones-type reflection matrix R have been known for decades, but have not been rigorously confirmed in experiments. Here, the authors have verified that the MOKE coefficients of R describe an ellipsoid (ellipse) for a random three-dimensional (two-dimensional) magnetization vector as predicted. The experiments accomplish the simultaneous measurements of all R components through generalized magneto-optical ellipsometry. | | | | | | Editors' Suggestion Raffaele Mazzilli, Alex Levchenko, and Elio J. König Phys. Rev. B 108, 014425 (2023) – Published 24 July 2023  | Probing quantum spin liquid behavior in atomically thin materials is a challenging task. The authors propose here an experimental setup consisting of two metallic layers separated by a thin quantum spin liquid. The voltage induced in one of the metals by injecting a current in the other metal probes the nontrivial dynamics of gapless excitations in the quantum spin liquid. This analysis captures U(1) and ℤ2 quantum spin liquids and may find realizations in materials such as α-RuCl3, 1T-TaSe2, and 1T-TaS2. | | | | | | Editors' Suggestion Rune Højlund, Emil Grovn, Sahar Pakdel, Kristian S. Thygesen, and Fredrik Nilsson Phys. Rev. B 108, 014506 (2023) – Published 20 July 2023  | van der Waal heterostructures can host long-lived excitons that can condense and exhibit superfluidity at low temperatures. In this paper, Højlund, Grovn and coworkers derive a first-principles framework, based on existing open-source codes, that can be used to model these systems. This framework is then used to evaluate the exciton binding energies and superfluid properties of hundreds of different heterostructures. Based on these calculations, the authors propose optimized materials with superior properties compared to the standard platforms. | | | | | | Editors' Suggestion T. Kouchi, K. Yoshinaga, T. Asano, S. Nishioka, M. Yashima, H. Mukuda, A. Iyo, T. Kawashima, and S. Miyasaka Phys. Rev. B 108, 014507 (2023) – Published 20 July 2023  | Since the discovery of the iron-based high-temperature superconductors, the superconductivity mechanism related to spin fluctuations and nematic (orbital) fluctuations has been much discussed, but it is remains unclear. Here, the authors reveal that the isotope 121,123Sb nuclei with large quadrupole moments are a sensitive local probe to observe the dynamics of orbital degrees of freedom. This provides us with a new approach to investigate systematically the correlation between the superconductivity and both the nematic and spin fluctuations, even in polycrystalline samples. | | | | | | Editors' Suggestion Katerina P. Hilleke, Xiaoyu Wang, Dongbao Luo, Nisha Geng, Busheng Wang, Francesco Belli, and Eva Zurek Phys. Rev. B 108, 014511 (2023) – Published 31 July 2023  | The recent results describing a room-temperature superconductor in the lutetium nitrogen hydrogen system have prompted an avalanche of work. In this computational study, a range of techniques from crystal structure prediction to prototype modification, produce an array of low-pressure dynamically stable Lu-N-H phases. None were thermodynamically stable. The best fit to the experimental EOS came from fluorite-type LuH2, while the highest estimated Tc (a meager 17 K) arose from an extremely thermodynamically unstable phase based on 50% N substitution (LuNH) | | | | | | Editors' Suggestion Pierre-Antoine Graham, Simon Bertrand, Michaël Bédard, Robin Durand, and Ion Garate Phys. Rev. B 108, 024301 (2023) – Published 5 July 2023  | For decades, van Roosbroeck's (VR) equations have been used to model microelectronic devices made from ordinary semiconductors. The advent of topological materials raises a largely unexplored question: how are VR equations and their solutions modified when electronic bands are topological? Here, the authors solve VR equations analytically in a Weyl semimetal placed under a magnetic field and subjected to a spatially inhomogeneous light pulse. They predict photoinduced plasma oscillations, which originate from a topological term in VR equations. | | | | | | Editors' Suggestion M. Ogino, Y. Kaneko, Y. Tokura, and Y. Takahashi Phys. Rev. B 108, 024418 (2023) – Published 20 July 2023  | Dynamical magnetoelectric coupling gives rise to nonreciprocal phenomena for light such as the optical diode effect and the nonreciprocity of light polarization. Here, the authors comprehensively study these nonreciprocal optical effects resonantly enhanced by electromagnons for multiferroic spin spiral states of perovskite manganites. The giant nonreciprocity observed near the phase boundary demonstrates an important role of anharmonicity of spin excitations for these nonreciprocal effects. Furthermore, they find one of the largest values for the dynamical magnetoelectric coupling on the resonance of electromagnons. | | | | | | Editors' Suggestion S. Tacchi, R. Silvani, M. Kuepferling, A. Fernández Scarioni, S. Sievers, H. W. Schumacher, E. Darwin, M.-A. Syskaki, G. Jakob, M. Kläui, and G. Carlotti Phys. Rev. B 108, 024430 (2023) – Published 31 July 2023  | Brillouin light scattering (BLS) experiments assisted by micromagnetic simulations show that the difference in frequency between counterpropagating spin waves in extended films and multilayers, induced by interfacial Dzyaloshinskii–Moriya interaction (i-DMI), is strongly reduced when lateral confinement is introduced. This poses a limit to the exploitation of BLS to quantify the i-DMI strength in the case of magnetic elements, such as dots and wires, with lateral dimensions below about 400 nm. | | | | | | Editors' Suggestion Ivan Fotev, Stephan Winnerl, Saicharan Aswartham, Sabine Wurmehl, Bernd Büchner, Harald Schneider, Manfred Helm, and Alexej Pashkin Phys. Rev. B 108, 035101 (2023) – Published 5 July 2023  | Application of pressure offers a way to continuously tune the ground state of a system across different phases realizing so-called quantum phase transitions. However, studying the order parameter is challenging because some established experimental techniques are not compatible with diamond anvil pressure cells. Here, the authors show that ultrafast pump-probe spectroscopy is an efficient method to accomplish this task. Using this approach, they succeed in mapping the spin density wave order parameter in iron-based superconductor BaFe2As2 over a broad range of pressures and temperatures. | | | | | | Editors' Suggestion Jiabin Yu, Ming Xie, B. Andrei Bernevig, and Sankar Das Sarma Phys. Rev. B 108, 035129 (2023) – Published 17 July 2023  | A topological heavy-fermion (THF) model is formulated for magical-angle twisted symmetric trilayer graphene (MATSTG), where "symmetric" means that the top and bottom layers are rotated equally with respect to the middle layer. In addition to the localized f modes and itinerant c modes (which serve as the basis of the THF model for twisted bilayer graphene), the THF model of MATSTG consists of extra Dirac (d) modes. The newly proposed f−c−d THF model can well reproduce previous numerical results on the correlated phases at integer fillings, and can provide a new analytical understanding of them at charge neutrality. | | | | | | Editors' Suggestion Pak Kau Lim, Michael Mulligan, and Jeffrey C. Y. Teo Phys. Rev. B 108, 035136 (2023) – Published 18 July 2023  | Interactions are crucial in driving topological phenomena in bosonic systems. Here, the authors construct exactly solvable models of topological phases of interacting bosons that preserve electric charge. They focus on the E8 bosonic integer quantum Hall state and show how its intrinsic E8 symmetry allows for the emergence of fractional topological phases of bosons. They detail the charge and statistics of the quasiparticle excitations of the resulting fractional quantum Hall states. | | | | | | Editors' Suggestion Y. Lee, R. Skomski, X. Wang, P. P. Orth, Y. Ren, Byungkyun Kang, A. K. Pathak, A. Kutepov, B. N. Harmon, R. J. McQueeney, I. I. Mazin, and Liqin Ke Phys. Rev. B 108, 045132 (2023) – Published 19 July 2023  | The kagome magnets RMn6Sn6 have recently emerged as a new topological materials platform. By elucidating the topological nature of the band structure, the authors conclude that the observed anomalous Hall conductivity is unrelated to the previously speculated quasi-two-dimensional Dirac points. The microscopic origin of magnetocrystalline anisotropy is explored at various levels: phenomenological, analytical, and ab initio. The authors discovered how the special Mn coordination of the rare-earth atoms results in significant high-order anisotropy. | | | | | | Editors' Suggestion Anuj Apte, Clay Córdova, and Ho Tat Lam Phys. Rev. B 108, 045134 (2023) – Published 20 July 2023  | Our understanding of quantum symmetry of systems has considerably broadened over the last decade. The idea of symmetry has become intrinsically linked with topology described and algebraically characterized by higher categories. Studying three-dimensional systems with noninvertible symmetries, the authors show here that these symmetries are in general incompatible with a unique gapped ground state. Their results extend the ideas behind the Lieb-Shultz-Mattis theorem to the arena of higher-dimensional field theories invariant under a novel class of symmetries. | | | | | | Featured in Physics Lixin Ge Phys. Rev. B 108, 045406 (2023) – Published 14 July 2023  | A friction-like quantum force could accelerate the motion of a rotating nanometer-diameter sphere when the sphere sits next to a graphene-coated surface. | | | | | | Editors' Suggestion Letter Yang Sun, Feng Zhang, Shunqing Wu, Vladimir Antropov, and Kai-Ming Ho Phys. Rev. B 108, L020101 (2023) – Published 10 July 2023  | The near-ambient superconductivity of nitrogen-doped lutetium hydride remains a contentious topic. This paper discusses how pressure and nitrogen doping affect the stability of lutetium trihydride. The authors propose a structural model that illustrates improved stability by substituting hydrogen atoms with nitrogen and introducing vacancies. However, the study uncovers no theoretical evidence for strong electron-phonon coupling in these phases. These findings provide a possible way to understand the experimental structure and offer insights for future superconductivity investigations into this intriguing compound. | | | | | | Editors' Suggestion Letter Alberto Nardin, Eddy Ardonne, and Leonardo Mazza Phys. Rev. B 108, L041105 (2023) – Published 18 July 2023  | Forty years ago, Laughlin explained the newly discovered fractional quantum Hall effect by proposing his famous wave function. He predicted the existence of anyons, particles with fractional charge, obeying fractional statistics. The fractional charge was confirmed almost thirty years ago, while the fractional statistics was observed only a few years back. In this paper, the authors focus on yet another fundamental property of the anyons, namely their spin. They derive a "spin-statistics relation" for anyons in fractional quantum Hall states, directly from the microscopic theory. This relation is a generalization of the fundamental "spin-statistics relation" that all ordinary particles obey. | | | | | | Editors' Suggestion Letter Yuxuan Jiang, Tianhao Zhao, Luojia Zhang, Qiang Chen, Haidong Zhou, Mykhaylo Ozerov, Dmitry Smirnov, and Zhigang Jiang Phys. Rev. B 108, L041202 (2023) – Published 26 July 2023  | The topological phases and their dependence on the lattice constant in zirconium pentatelluride ZrTe5 have been under heated debate. Here, the authors study the temperature evolution of the Dirac band in ZrTe5 and find no indication of band-gap closure as temperature changes. They show that a weak topological insulator phase across the temperature range may not be the only explanation. A topological phase transition is still possible if the band mixing and inversion are considered. | | | | | | Editors' Suggestion Letter Z. An, P. Soubelet, Y. Zhumagulov, M. Zopf, A. Delhomme, C. Qian, P. E. Faria Junior, J. Fabian, X. Cao, J. Yang, A. V. Stier, F. Ding, and J. J. Finley Phys. Rev. B 108, L041404 (2023) – Published 20 July 2023  | The spin-valley physics of monolayer transition metal dichalcogenides (TMDs) remains one of the main interests in the class of van der Waals materials. At low temperature, it is mainly driven by the electron-hole exchange interaction (EHEI) that describes the annihilation of an exciton in one valley and the creation of an exciton in the time-reversal equivalent valley. Here, the authors show that the EHEI in monolayer TMDs is biaxial strain dependent and, surprisingly, it is an order of magnitude more strain dependent than expected from these first principles calculations. This points to a valley scattering channel that has not been considered in the literature so far. | | | | | | | |
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