| Volume 108, Issues 5 - 8 August 2023 | | Advertisement | Abstract submissions are officially open for the APS March Meeting 2024! Showcase your work to a global audience of physicists, scientists, and students representing 32 APS Units and Committees and explore groundbreaking research from industry, academia, and major labs. Start preparing your abstract and be sure to submit it by October 20. Submit an abstract. | | | | | | Not an APS member? Join today to start connecting with a community of more than 50,000 physicists. | | | | Mark Dykman, Alexander Efros, Bertrand Halperin, Leonid Levitov, and Charles Marcus Phys. Rev. B 108, 050001 (2023) – Published 1 August 2023 | | | Editors' Suggestion Zihao Qi, Thomas Scaffidi, and Xiangyu Cao Phys. Rev. B 108, 054301 (2023) – Published 1 August 2023  | Quantum dynamics of spin systems with uniform infinite-range interaction are often considered "simple" because they become semiclassical in the thermodynamic limit. However, the standard semiclassical theory only applies to a shallow surface of the vast many-body Hilbert space. What happens away from this? Here, the authors dive into the "deep Hilbert space" and unveil a number of exotic phenomena in this rarely charted territory. | | | | | | Editors' Suggestion A. M. Vibhakar, D. D. Khalyavin, P. Manuel, N. J. Steinke, L. Zhang, K. Yamaura, A. A. Belik, and R. D. Johnson Phys. Rev. B 108, 054403 (2023) – Published 3 August 2023  | The authors show here that the introduction of substitutional disorder in the presence of competing exchange interactions causes the [Y2−xMnx]Mn6O12 quadruple perovskite manganites to develop short-range antiferromagnetic clusters contained in a paramagnetic matrix, before transitioning to a phase characterized by well correlated long-range ferrimagnetic order that coexists with the short-range antiferromagnetic clusters. It is spin doping through the substitution of magnetic Mn ions for nonmagnetic Y ions that gives rise to a spin texture that is inhomogeneous on the nanoscale. | | | | | | Editors' Suggestion Christopher Roth, Attila Szabó, and Allan H. MacDonald Phys. Rev. B 108, 054410 (2023) – Published 8 August 2023  | Establishing quantum spin liquid physics in microscopic models is a daunting task due to a variety of competing low-energy states, requiring sophisticated computational approaches to find the true ground state. Here, the authors present such a technique, based on neural networks with space-group symmetry, to obtain significantly improved ground-state wave functions of frustrated Heisenberg models. The authors also use this approach to find excited states and provide a blueprint for testing analytical predictions from spin-liquid theories. | | | | | | Editors' Suggestion Chiara Bigi, Lei Qiao, Chao Liu, Paolo Barone, Monica Ciomaga Hatnean, Gesa-R. Siemann, Barat Achinuq, Daniel Alexander Mayoh, Giovanni Vinai, Vincent Polewczyk, Deepak Dagur, Federico Mazzola, Peter Bencok, Thorsten Hesjedal, Gerrit van der Laan, Wei Ren, Geetha Balakrishnan, Silvia Picozzi, and Phil D. C. King Phys. Rev. B 108, 054419 (2023) – Published 11 August 2023  | This work establishes the spectroscopic fingerprints of ferrimagnetic Mn3Si2Te6, providing a comprehensive understanding of the electronic states underpinning its magnetic interactions. The authors show the pivotal role played by covalency, which weakens the electronic correlations and influences the magnetic frustrations and anisotropic exchange, leading to the onset of the long-range ferrimagnetic order in this compound. The approach of combining spectroscopic experiments with state-of-the-art first-principles theory will have widespread applicability across the families of layered and quasilayered magnetic materials. | | | | | | Editors' Suggestion Shiyi Zheng, Hongliang Wo, Yiqing Gu, Rui Leonard Luo, Yimeng Gu, Yinghao Zhu, Paul Steffens, Martin Boehm, Qisi Wang, Gang Chen, and Jun Zhao Phys. Rev. B 108, 054435 (2023) – Published 23 August 2023  | Emerging as a platform for novel quantum effects, triangular-lattice rare-earth delafossite compounds have attracted significant attention. This study investigates KTmSe2 using thermodynamic and neutron scattering methods, revealing highly dispersive crystal electric field excitations. From the transverse field Ising model and a full crystal field scheme, the findings uncover a strong interplay between spin exchange interactions and crystal field effects. These insights will provide a valuable framework for understanding low-temperature magnetism in materials of a similar type. | | | | | | Editors' Suggestion Syed Q. A. Shah, Ather Mahmood, Arun Parthasarathy, and Christian Binek Phys. Rev. B 108, 054437 (2023) – Published 25 August 2023  | The discovery of a monopole contribution to the overall magnetoelectric susceptibility of Cr2O3 sparked the search for a material with pure monopole response. Magnetoelectric powder samples are alternatives to magnetic topological insulators which, in practice, are not suitable candidates. Here, the authors experimentally and theoretically investigate the magnetoelectric susceptibility of Cr2O3 powder. Although electric and magnetic field cooling tunes the susceptibility, there is no field-cooling protocol that leads to a pure monopole response. These insights provide alternatives to realize effective magnetoelectric monopole media. | | | | | | Editors' Suggestion Jae Hyuck Lee, Dirk Wulferding, Junkyoung Kim, Dongjoon Song, Seung Ryong Park, and Changyoung Kim Phys. Rev. B 108, 054443 (2023) – Published 31 August 2023  | Transition metal pyrochlore oxides are prototypical platforms for exploring and engineering a plethora of magnetic phases based on the intimate interplay of charge, lattice, and spin degrees of freedom. Here, the authors conduct Raman spectroscopic experiments on a series of pyrochlore ruthenates and identify one-magnon modes. They find a remarkably simple proportional relation between the Néel temperature and magnon energy, inferring that the compounds host common spin structures. This work showcases the straightforward tunability of the magnon band structure based on the A-site ion in A2Ru2O7. | | | | | | Editors' Suggestion Christina Psaroudaki and Gil Refael Phys. Rev. B 108, 064301 (2023) – Published 1 August 2023  | Quantum machines have been a fascination for years. This paper examines a specific quantum machine - a spin driven by two harmonically related light beams. When the spin adopts a specific Floquet state, it receives energy from one beam and transfers it to the other, acting as an energy frequency converter. The authors study the power distribution of this 2-beam and spin system, uncovering an intriguing transition in distribution width, tuned by the drive amplitude. | | | | | | Editors' Suggestion Ammar Kirmani, Derek S. Wang, Pouyan Ghaemi, and Armin Rahmani Phys. Rev. B 108, 064303 (2023) – Published 2 August 2023  | Using a noisy quantum computer, the authors emulate direct braiding in a fractional quantum Hall system via a simplified model for a thin cylinder. The quantum algorithm prepares a ground state with two quasiholes, performs a unitary operation controlled by an ancilla to move one quasihole around the other, and measures the ancilla with error mitigation to extract the wave function's acquired phase. This approach offers a method for studying braiding statistics in fractional Hall states in digitized devices. | | | | | | Editors' Suggestion Eli Zoghlin, Matthew B. Stone, and Stephen D. Wilson Phys. Rev. B 108, 064408 (2023) – Published 9 August 2023  | Quasi-one-dimensional materials serve as both testbeds for tractable magnetic models and as a perennial source of intriguing physics. An excellent example is the emergence of multimagnon bound states in ferromagnetic (FM) spin chains, which provide a platform for probing a few-body quantum phenomenon. Despite being studied for many years, the exchange anisotropy-driven bound state of a FM chain has yet to be observed by inelastic neutron scattering (INS). As INS provides a unique window into the nature of magnon-magnon interactions, this represents a substantive gap in the literature. Here, the authors rectify this gap by presenting detailed INS data on the S=½ spin chain Li2CuO2. Their data allows for determination of a refined spin Hamiltonian which fully describes the one-magnon dispersion. With these details in hand, they demonstrate the existence of two-magnon and, potentially, three-magnon bound states in Li2CuO2, with the potential three-magnon bound state showing anomalous behavior. | | | | | | Editors' Suggestion Jonathan Z. Sun, Christopher Safranski, Philip Trouilloud, Christopher D'Emic, Pouya Hashemi, and Guohan Hu Phys. Rev. B 108, 064418 (2023) – Published 15 August 2023  | Superparamagnetic fluctuation of a nanomagnet, when confined by a strong easy-plane anisotropy, can yield a GHz-speed random signal. A magnetic tunnel junction converts such moment movement into conductance fluctuation and is useful as an entropy source for modern computing circuits. Here, the authors experimentally explore a magnetic tunnel junction with a synthetic antiferromagnetically coupled free layer and reference layer, in their superparamagnetic limit, to demonstrate hardware-based generation of a Gb/sec random bit stream, and to learn of factors in device materials and the fabrication process that are in need of future optimization. | | | | | | Editors' Suggestion Yong-Chang Lau, Junya Ikeda, Kohei Fujiwara, Akihiro Ozawa, Jiaxin Zheng, Takeshi Seki, Kentaro Nomura, Liang Du, Quansheng Wu, Atsushi Tsukazaki, and Koki Takanashi Phys. Rev. B 108, 064429 (2023) – Published 25 August 2023  | This work establishes the pivotal role of topological bands in the magnetic Weyl semimetal prototype Co3Sn2S2 for efficient generation of spin current at room temperature via the spin Hall effect. Electron and hole-doped shandite films are systematically studied to map the evolution of Hall conductivities against Fermi level tuning. The authors demonstrate that the observed anomalous Hall conductivity and spin Hall conductivity maxima at distinct doping levels share the common origin in the band structure, suggesting such a correlation can be exploited for screening materials with large transverse magnetoelectric responses. | | | | | | Mark Dykman, Alexander Efros, Bertrand Halperin, Leonid Levitov, and Charles Marcus Phys. Rev. B 108, 070001 (2023) – Published 1 August 2023 | | | Editors' Suggestion Stefano Longhi Phys. Rev. B 108, 075121 (2023) – Published 8 August 2023  | Strongly correlated systems in non-Hermitian models are an emergent area of research. Here, the author considers the correlated hopping dynamics of two fermions in a quasicrystal with a complex phase, unraveling non-Hermitian-induced mobility edges and the tendency of the fermions to stick together, forming a doublon state in the long time limit of evolution, a phenomenon that can be dubbed non-Hermitian particle bunching. | | | | | | Editors' Suggestion Junsong Sun, Chang-An Li, Shiping Feng, and Huaiming Guo Phys. Rev. B 108, 075122 (2023) – Published 9 August 2023  | The hyperbolic lattice, existing in a space of constant negative curvature, displays unique physical properties compared to its Euclidean counterpart, and has garnered significant attention recently. Here, the authors have proposed the existence of a higher-order skin-topological effect in hyperbolic lattices. This result first introduces a non-Hermitian effect into hyperbolic lattices, which extends the regime of topological phases with hyperbolic geometry. | | | | | | Editors' Suggestion Abhishek Kumar, Premala Chandra, and Pavel A. Volkov Phys. Rev. B 108, 075162 (2023) – Published 28 August 2023  | In spin-orbit coupled metals, polar phonons couple to the spin of electrons by inducing a dynamical Rashba-type spin splitting. Here, the authors study the consequences of such coupling in polar metals, where one of the polar phonons has undergone a symmetry-breaking transition. They show that application of magnetic field reveals a spectrum of collective modes that can change their character (electronic vs. lattice) and energy as a function of field strength. Optical spectroscopy experiments are shown to have the capability to probe these modes. | | | | | | Editors' Suggestion Dylan Lewis, João P. Moutinho, Antonio T. Costa, Yasser Omar, and Sougato Bose Phys. Rev. B 108, 075405 (2023) – Published 9 August 2023  | The transport of information is an essential component of both classical and quantum computers. Coherent quantum dynamics offers the potential for the transfer of information through a linear array of quantum dots almost without dissipation. Here, the authors describe a protocol and calculate the energetic cost of transferring quantum states as a quantum or classical data bus, showing its advantage over the shuttling of electrons and classical data buses. | | | | | | Editors' Suggestion Valentin Leeb and Johannes Knolle Phys. Rev. B 108, 085106 (2023) – Published 3 August 2023  | The Fermi surface — the manifold of gapless excitations forming due to Pauli's famous exclusion principle— determines all electronic properties of metals. In 1952 Lars Onsager discovered how to measure a Fermi surface by studying the response of a metallic material as a function of an applied magnetic field. In fact, observables like electrical resistivity or the magnetization oscillate as a function of inverse field. Onsager's relation forms the basis for our understanding of electronic properties of metals and is used in many experimental labs around the world. Here, the authors find that, in the presence of strong interactions between electrons, Onsager's relation can be violated and they provide the first rigorous calculations of this effect. In general, solving for the emergent Landau levels of a strongly interacting material in a magnetic field is a hard problem. The methodological progress made here is enabled by concentrating on an exactly soluble model with infinite-range interactions. This research establishes the importance of inter Landau level interactions for understanding correlated materials in magnetic fields. | | | | | | Editors' Suggestion Aidan P. Reddy, Faisal Alsallom, Yang Zhang, Trithep Devakul, and Liang Fu Phys. Rev. B 108, 085117 (2023) – Published 15 August 2023  | The recent observation of the fractional quantum anomalous Hall effect opens a new frontier in topological phases and quantum materials. Here, the authors demonstrate that the strong interaction in partially filled topological moiré bands of twisted semiconductor bilayers induces a variety of phases, including ferromagnetic metals, charge density waves, and fractional quantum anomalous Hall states. This work reveals a remarkably rich phase diagram as a function of twist angle, awaiting further exploration. | | | | | | Editors' Suggestion S. Ernst, P. J. Scheidegger, S. Diesch, and C. L. Degen Phys. Rev. B 108, 085203 (2023) – Published 24 August 2023  | The nitrogen vacancy (NV) center in diamond is well known for its outstanding optical and spin properties, enabling various applications in quantum sensing and quantum information at both cryogenic and ambient temperatures. Despite a large body of work, however, the NV center's dynamics at intermediate temperatures are incompletely understood. This paper describes a basic rate model able to explain the NV population dynamics over the full parameter space of temperature, crystallographic strain, and magnetic field. Numerical simulations of the model are in excellent agreement with experiments discussed in the accompanying PRL. | | | | | | Editors' Suggestion H. Ishida Phys. Rev. B 108, 085401 (2023) – Published 2 August 2023  | There is currently large interest in the orbital Rashba effect at crystal surfaces. Here, the author investigates the orbital angular momentum induced spin splitting of surface states on Au(110) by first-principles calculations. It is revealed that although the p component of the orbital angular momentum is much smaller than the d component, the former gives rise to a large anisotropy in the orientation dependence of spin-splitting energies. This is because the spin-orbit coupling parameter for the p orbital of Au is several times larger than that for the d orbital. | | | | | | Editors' Suggestion Letter Raja Sen, Nathalie Vast, and Jelena Sjakste Phys. Rev. B 108, L060301 (2023) – Published 16 August 2023  | It is commonly believed that phonon drag, a phenomenon where electrons are dragged from the hot to the cold side of the sample by out-of-equilibrium phonons, does not play any significant role on the nanoscale. Here, the authors show that, even if the phonon-drag contribution is strongly reduced by nanostructuring, a silicon thin film of 100 nm thickness can still preserve more than 20% of the bulk phonon-drag contribution at 300 K along the in-plane direction of the thin film. | | | | | | Editors' Suggestion Letter Jianyong Chen, Wei Qin, Ping Cui, and Zhenyu Zhang Phys. Rev. B 108, L060501 (2023) – Published 4 August 2023  | Ferroelectricity, superconductivity, and topology are three cornerstone concepts of condensed matter physics, and integration of any two may further fertilize exotic emergent phenomena. To date, harmonic coexistence of all three remains to be materialized. Here, the authors predict simultaneous tuning of superconducting transition temperature and band topology by ferroelectricity, with a heterobilayer of superconducting IrTe2 and ferroelectric In2Se3 as a physically realistic example. Such reversible and nonvolatile tunabilities may find important applications in novel superconducting devices and topological quantum computation. | | | | | | Editors' Suggestion Letter Ryan S. Russell, Hari P. Nair, Kyle M. Shen, Darrell G. Schlom, and John W. Harter Phys. Rev. B 108, L081105 (2023) – Published 9 August 2023  | The nature of unconventional superconductivity in Sr2RuO4 remains stubbornly unresolved, and it is clear that a fundamental piece of the puzzle is still missing. Here, the authors use static and ultrafast optical dichroism measurements to uncover signatures of electronic nematic order in high quality epitaxially strained thin films of Sr2RuO4. Through the development of a simple Ising model of the nematic order, the authors show that optical pumping induces a coherent oscillation of its amplitude mode. Whether and how this nematic order ultimately influences the superconductivity in Sr2RuO4 remains a key open question. | | | | | | Editors' Suggestion Letter Tharindu Fernando and Ting Cao Phys. Rev. B 108, L081111 (2023) – Published 15 August 2023  | Classifying the multiband topology of two-dimensional parameter space submanifolds, exemplified by electron valleys in a Brillouin zone, has historically been a complex endeavor. In response to these limitations, the authors unveil here a gauge-invariant, quantized interband topological index. This refined approach enhances the classification of valleys, and additionally sheds light on the nature of edge states resulting from band inversions in multiband systems. These findings deepen our grasp of valley physics and the intricacies of interband topology. | | | | | | Editors' Suggestion Letter Yi-Ming Wu, Ronny Thomale, and S. Raghu Phys. Rev. B 108, L081117 (2023) – Published 22 August 2023  | Pair density wave superconductivity arises when the two paired fermions have finite center-of-mass momentum. It is usually not a weak coupling instability and requires stringent conditions, such as the pairing interaction remaining attractive at finite momentum, and the interaction strength has to be strong enough. Here, the authors find that the kagome lattice model, when doped to a particular Van Hove filling with both onsite and nearest neighbor repulsion, can serve as an ideal platform for realizing this novel superconducting state. | | | | | | Editors' Suggestion Letter Mengxing Ye and Andrey V. Chubukov Phys. Rev. B 108, L081118 (2023) – Published 22 August 2023  | It is known that thermal magnetic fluctuations can give rise to pseudogap behavior in a paramagnetic metal. However, the role of vertex corrections for the pseudogap formation is not well understood. The authors show here that without vertex corrections there is no pseudogap, but an inclusion of even infinitesimally small vertex corrections gives rise to pseudogap behavior. The authors further generalize this statement to a set of boundary models, in which the pseudogap develops upon inclusion of perturbations. This work provides an understanding of recent numerical studies of the pseudogap. | | | | | | Editors' Suggestion Letter H. Liu, M. Lee, M. Šiškins, H. S. J. van der Zant, P. G. Steeneken, and G. J. Verbiest Phys. Rev. B 108, L081401 (2023) – Published 2 August 2023  | The speed of sound and flexural phonons in two-dimensional materials depends strongly on the tension in these ultraflexible membranes. Here, the authors experimentally demonstrate that freestanding graphene membranes cool down 33% faster when increasing tension by electrostatic gating. They attribute this effect mainly to improved acoustic impedance match of flexural phonons at the boundaries of the membrane and thus provide a route towards electronic devices and circuits for high-speed control of nanoscale heat transport. | | | | | | | |
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