| Volume 107, Issues 9 - 12 March 2023 | |
Advertisement | APS is seeking nominations for all APS Honors, recognizing outstanding achievements in physics. Nominate a colleague for APS Fellowship, Prizes, and Awards. They are open to all members of the scientific community. Please consider nominating deserving colleagues. Learn more. | | | | | | Not an APS member? Join today to start connecting with a community of more than 50,000 physicists. | | | | Editors' Suggestion Marisel Di Pietro Martínez, Alexis Wartelle, Carlos Herrero Martínez, Farid Fettar, Florent Blondelle, Jean-François Motte, Claire Donnelly, Luke Turnbull, Feodor Ogrin, Gerrit van der Laan, Horia Popescu, Nicolas Jaouen, Flora Yakhou-Harris, and Guillaume Beutier Phys. Rev. B 107, 094425 (2023) – Published 22 March 2023  | The authors present a new tomographic technique, based on Fourier transform holography. It is a lensless imaging technique to retrieve the object of interest from its diffraction pattern in a single step of computation. A combination of dual-axis tomographic projections provides a 3D vectorial magnetic image of an 800-nm-thick Fe/Gd multilayer in a 5-μm-diameter field of view with a resolution of 80 nm. The reconstruction reveals not only wormlike domains with magnetization pointing mostly out of plane, but also the subtle features of magnetic flux closure around the domain walls. | | | | | | Editors' Suggestion Aaron Chew, Yijie Wang, B. Andrei Bernevig, and Zhi-Da Song Phys. Rev. B 107, 094512 (2023) – Published 17 March 2023  | Twisted bilayer graphene, by nature of its symmetries (like the approximate particle-hole symmetry) and anomalous band structure, realizes a higher-order topological superconductor when s-wave pairing is introduced via proximity. Here, the authors demonstrate this exotic phase numerically and analytically, and illustrate a multitude of consequences: zero modes bound to Abrikosov vortices, the fractional Josephson effect, and much more. | | | | | | Editors' Suggestion Jonas F. Karcher, Ilya A. Gruzberg, and Alexander D. Mirlin Phys. Rev. B 107, 104202 (2023) – Published 22 March 2023  | Anderson transitions between metals and insulators exhibit fascinating spatial structure, fluctuations, and correlations of electronic wave functions. This structure has been properly characterized by the authors in terms of multifractals with continuous spectra of scaling exponents. In this paper, the authors focus on Anderson transitions in systems with a sublattice (chiral) symmetry. This particular class of Anderson transitions has not been well-studied in the past, and the authors fill this gap with a thorough analytical and numerical study of multifractal spectra in the metallic phase and at the critical point of the Anderson transition. | | | | | | Editors' Suggestion Robert Oliva, Esther Ritov, Faris Horani, Iñigo Etxebarria, Adam K. Budniak, Yaron Amouyal, Efrat Lifshitz, and Mael Guennou Phys. Rev. B 107, 104415 (2023) – Published 16 March 2023  | Antiferromagnetic MnPS3 and diamagnetic ZnPS3 belong to a family of two-dimensional compounds that exhibit a rich variety of magnetic ordering. Low-temperature Raman spectroscopy and SQUID magnetometer measurements are performed on both compounds and their alloy in order to evaluate a possible Jahn-Teller distortion as well as to reveal magnetic and alloy signatures. With the aid of first-principles calculations, a description of the lattice dynamics of the system is presented, together with the magnetic phase diagram across the entire compositional range. | | | | | | Editors' Suggestion N. Matsuyama, T. Nomura, S. Imajo, T. Nomoto, R. Arita, K. Sudo, M. Kimata, N. D. Khanh, R. Takagi, Y. Tokura, S. Seki, K. Kindo, and Y. Kohama Phys. Rev. B 107, 104421 (2023) – Published 21 March 2023  | The skyrmion formation mechanism in centrosymmetric systems remains to be understood, partially because of the lack of fundamental understanding of the electronic structure. The authors observe de Haas–van Alphen and Shubnikov–de Haas oscillations in high magnetic fields up to 58 T on GdRu2Si2, which is one of such centrosymmetric skyrmion-hosting magnets with the shortest skyrmion diameter ever found. Combined with first-principles calculations, the authors now reveal the electronic structure of GdRu2Si2 and its reconstruction at the magnetic phase boundary. | | | | | | Editors' Suggestion Amanda Ehn, Björn Alling, and Igor A. Abrikosov Phys. Rev. B 107, 104422 (2023) – Published 21 March 2023  | Beside the classic Fe64Ni36 Invar alloy, which shows an anomalously low thermal expansion at ambient pressure, Fe-Ni alloys with a higher nickel composition can be driven to Invar behavior by pressure. The authors investigate the pressure induced Invar effect theoretically and demonstrate that it can be explained by a magnetic transition from a ferromagnetic state at high volume to a complex noncollinear state upon compression. They relate the Invar effect to the increasing contribution of magnetic entropy with pressure. | | | | | | Editors' Suggestion J. Gaudet, H.-Y. Yang, E. M. Smith, T. Halloran, J. P. Clancy, J. A. Rodriguez-Rivera, Guangyong Xu, Y. Zhao, W. C. Chen, G. Sala, A. A. Aczel, B. D. Gaulin, F. Tafti, and C. Broholm Phys. Rev. B 107, 104423 (2023) – Published 22 March 2023  | The rare-earth monopnictides RX have been found to exhibit exotic topological three-dimensional states, coupled to unique magnetotransport responses such as extreme magnetoresistance. These findings generated interest to understand the interplay between electronic band topology, transport, and magnetism in RX. While neutron scattering is indispensable to fully characterize magnetism, there is very little modern work on this family of compounds. Since the details of the magnetism have a profound impact on the electronic band topology and transport in materials, the authors present here a thorough characterization of the magnetism in HoBi, based on modern neutron scattering techniques. | | | | | | Editors' Suggestion Danila Amoroso, Bertrand Dupé, and Matthieu J. Verstraete Phys. Rev. B 107, 104427 (2023) – Published 28 March 2023  | Magnetic rare-earth orthoferrite perovskites (RFeO3) host a variety of functional properties particularly suitable for next-generation, ultrafast spintronic devices. A key ingredient is the complex magnetic interaction at play between the two magnetic substructures. SmFeO3 has attracted particular interest because of its high-temperature spin reorientation transition and anomalous temperature-dependent lattice vibrational modes. Through first-principles calculations, the authors unveil here the interplay of the Sm-Fe exchange with the strong Sm f anisotropy as the dominant microscopic mechanism, and the nature of the anomalous vibrations. | | | | | | Editors' Suggestion Areg Ghazaryan, Tobias Holder, Erez Berg, and Maksym Serbyn Phys. Rev. B 107, 104502 (2023) – Published 2 March 2023  | Multilayer graphene systems without a moiré superlattice have emerged as an alternative platform to study interaction and superconducting phases. This study systematically compares density of states of multilayer graphene with different stacking. It identifies tetralayer graphene with rhombohedral (ABCA) stacking as the most promising material for realization of broken-symmetry phases. In-depth analysis of the phase diagram of ABCA graphene shows that, for the accessible range of experimental parameters, the material supports corrugated Fermi surface, which can realize a topological p+ip superconducting state with chiral Majorana edge modes. | | | | | | Editors' Suggestion R. Chapai, M. P. Smylie, H. Hebbeker, D. Y. Chung, W.-K. Kwok, J. F. Mitchell, and U. Welp Phys. Rev. B 107, 104504 (2023) – Published 2 March 2023  | A15 materials have been studied extensively due to the importance of Nb3Sn for the fabrication of high-field superconducting magnets. Recently, their topological properties have generated substantial interest as these materials have potential to exhibit exotic phenomena, such as topological superconductivity and large spin Hall effect. Here, the authors employ various complementary bulk measurement techniques to characterize the superconducting properties of the A15 material Ti3Sb. They report modestly strong superconducting coupling, indications for paramagnetic limiting, and a full superconducting gap. | | | | | | Editors' Suggestion Bill P. Truong, Kartiek Agarwal, and T. Pereg-Barnea Phys. Rev. B 107, 104516 (2023) – Published 24 March 2023  | It is well known that Majorana zero modes can be harnessed for applications in topological quantum computation. Transitions away from the ground-state subspace, where computations are performed, are detrimental. The authors study the diabatic error which quantifies these transitions as Majorana zero modes are transported across a superconducting wire. Using the 'piano key' approach for transport, the authors find that there exists an optimal number of keys which reduces the diabatic error. | | | | | | Editors' Suggestion Daniel Azses, David F. Mross, and Eran Sela Phys. Rev. B 107, 115113 (2023) – Published 6 March 2023  | Entanglement spectra and their symmetries provide unique fingerprints of symmetry-protected topological states (SPTs). Unfortunately, using such calculations to identify SPTs numerically is notoriously difficult. Here, the authors develop a numerical method mapping this computation to a one-dimensional problem by utilizing the local nature of the quantum circuits that generate any SPT. Its application to models with Ising symmetry fully confirms field-theoretic predictions for their entanglement spectrum. Additionally, nontrivial deformations of the SPT manifest as many-body Aharonov-Bohm fluxes in the entanglement spectrum. | | | | | | Editors' Suggestion Stefano Di Sabatino, Alejandro Molina-Sánchez, Pina Romaniello, and Davide Sangalli Phys. Rev. B 107, 115121 (2023) – Published 9 March 2023  | The determination of an excitonic insulator phase relies on the relative value of the excitonic binding energy and the fundamental band gap. With the quite unique case of NiBr2, the authors warn about the risk of running into false positives when using the GW+BSE scheme to determine if a system displays negative excitonic energies, which are a signature of an excitonic insulator phase. They show that consistency between approximations used in the ground-state and excited-state calculations as well as independence from the starting point are essential features for a proper description of excitonic insulators. | | | | | | Editors' Suggestion J. Sears, Y. Shen, M. J. Krogstad, H. Miao, E. S. Bozin, I. K. Robinson, G. D. Gu, R. Osborn, S. Rosenkranz, J. M. Tranquada, and M. P. M. Dean Phys. Rev. B 107, 115125 (2023) – Published 10 March 2023  | The cuprate superconductors exhibit periodic modulations of their charge density and crystal structure. Using x-ray diffraction, the authors identify the subtle structural displacements associated with this ordering. The displacements are not confined to a single copper-oxygen layer but rather propagate over a surprisingly large distance through the crystal. The authors attribute this effect to the weak c-axis charge screening in cuprates and suggest that this effect could help couple the charge-density wave between adjacent planes in the crystal. | | | | | | Editors' Suggestion Penghao Zhu, A. Alexandradinata, and Taylor L. Hughes Phys. Rev. B 107, 115159 (2023) – Published 28 March 2023  | The authors introduce here a time-reversal-symmetric analog of the Hopf insulator, dubbed as a spin Hopf insulator. The spin Hopf insulator harbors surface Kane-Mele ℤ2 order and gapless helical hinge modes. Remarkably, the spin Hopf insulator is the first example of a nonmagnetic delicate topological insulator with spin-orbital coupling. In the presence of fourfold rotational symmetry, the spin Hopf insulator also exhibits a returning Thouless pump. These studies of nonmagnetic spin Hopf insulators provide a pathway towards realizing a Hopf material in experiments. | | | | | | Editors' Suggestion Andrea Amorese, Philipp Hansmann, Andrea Marino, Peter Körner, Thomas Willers, Andrew Walters, Ke-Jin Zhou, Kurt Kummer, Nicholas B. Brookes, Hong-Ji Lin, Chien-Te Chen, Pascal Lejay, Maurits W. Haverkort, Liu Hao Tjeng, and Andrea Severing Phys. Rev. B 107, 115164 (2023) – Published 29 March 2023  | Orbital selective coupling explains the exotic ferromagnetism in CeRh3B2, which combines a high Curie temperature, a strongly reduced ordered moment, strong intermediate valence, and a high Kondo temperature. The cigar-shaped Ce 4f |Jz = ½⟩ states couples with the Ce 5d states setting up the ferromagnetism, while the in-plane Ce 4f |Jz =⁵⁄₂⟩ hybridizes with the surrounding B states, forming the Kondo state. The image shows the crystal field potential of the Ce 4f states; the preferred directions of interaction are shown in blue, while the least favored ones are marked in red. | | | | | | Editors' Suggestion Bart Olsthoorn Phys. Rev. B 107, 115174 (2023) – Published 31 March 2023  | What shapes of entanglement are present in quantum states? Persistent homology provides an answer that contains both topological and geometrical information. This is a relatively new method from the field of topological data analysis, where shapes in discrete data are captured at varying length scales. In this case, the length scale is based on quantum mutual information, and the method is used to detect quantum phase transitions. | | | | | | Editors' Suggestion T. Johnsen, C. Schattauer, S. Samaddar, A. Weston, M. J. Hamer, K. Watanabe, T. Taniguchi, R. Gorbachev, F. Libisch, and M. Morgenstern Phys. Rev. B 107, 115426 (2023) – Published 24 March 2023  | Edge states are the fingerprint of topological materials, specifically of the quantum Hall effect. The authors map quantum Hall edge states along an electrostatically defined potential step in graphene using scanning tunneling microscopy. Tight-binding simulations reproduce the measurements and allow for identifying a parameter range that minimizes the influence of the tip. This enables investigating the edge states while avoiding tip-induced quantum dots within the sample. The image shows a measured edge state featuring the expected antinodal patterns as it meanders along the interface. | | | | | | Editors' Suggestion Seungho Seong, J. D. Denlinger, Kyoo Kim, B. I. Min, Y. Ōnuki, and J.-S. Kang Phys. Rev. B 107, 125109 (2023) – Published 3 March 2023  | The electronic structure of CeNiSn, a potential topological Kondo insulator and a Dirac nodal-loop semimetal, is investigated here employing temperature-dependent angle-resolved photoemission spectroscopy (ARPES). Dispersive states crossing the Fermi level (EF) exhibit general agreement with theoretical predictions of bulk Ni 3d bands and show consistency with a topological hourglass-type crossing of bulk bands below EF. Flat Ce 4f states at EF exhibit a Kondo resonance temperature dependence consistent with bulk transport. This work demonstrates the importance of coherent Kondo states in determining the topological properties of CeNiSn. | | | | | | Editors' Suggestion M. O. Ajeesh, P. Materne, R. D. dos Reis, K. Weber, S. Dengre, R. Sarkar, R. Khasanov, I. Kraft, A. M. León, W. Bi, J. Zhao, E. E. Alp, S. Medvedev, V. Ksenofontov, H. Rosner, H.-H. Klauss, C. Geibel, and M. Nicklas Phys. Rev. B 107, 125136 (2023) – Published 16 March 2023  | Competing ground states often lead to the emergence of novel unconventional phases. The presence of magnetic frustration in such materials brings about additional complexity. Here, the authors present a comprehensive study on the ground-state properties of LuFe4Ge2, a ternary intermetallic compound with magnetic frustration and quasi-one-dimensional structure, elucidating the interplay of structure and magnetism. In contrast to the well-studied two-dimensional iron pnictides with competing exchange interactions, LuFe4Ge2 exhibits quasi-one-dimensional chains of geometrically frustrated Fe tetrahedra. It displays a magnetostructural transition at ambient pressure with a change in symmetry from tetragonal to orthorhombic, similar to that in the iron-pnictides, which evolves in an unexpected way under the application of hydrostatic pressure. In that way the intermetallic LuFe4Ge2 material family offers a new perspective on the entanglement of crystal structure and magnetism. | | | | | | Editors' Suggestion Li-kun Shi, Oles Matsyshyn, Justin C. W. Song, and Inti Sodemann Villadiego Phys. Rev. B 107, 125151 (2023) – Published 27 March 2023  | Employing a detailed model of electrons coupled to a heat bath, this work demonstrates the generation of photocurrents when the frequency of light lies within the optical gap of a metal in the limit of small absorption. Such in-gap rectification is shown to be consistent with thermodynamic principles and is generally dissipative. The nonlinear Hall effect behaves, however, as a special dissipationless "demon" that can perform a highly efficient and reversible transfer of energy between the radiation and an external circuit. | | | | | | Editors' Suggestion Dipranjan Chatterjee, Pascal Puphal, Quentin Barthélemy, Jannis Willwater, Stefan Süllow, Christopher Baines, Sylvain Petit, Eric Ressouche, Jacques Ollivier, Katharina M. Zoch, Cornelius Krellner, Michael Parzer, Alexander Riss, Fabian Garmroudi, Andrej Pustogow, Philippe Mendels, Edwin Kermarrec, and Fabrice Bert Phys. Rev. B 107, 125156 (2023) – Published 28 March 2023  | Y3Cu9(OH)19Cl8, also known as Y-kapellasite, realizes an original anisotropic frustrated kagome model. Here, the authors study large phase-pure single crystals, obtained via an external gradient method, by susceptibility, specific heat, thermal expansion, neutron scattering, and local μSR and NMR techniques. These find subtle structural changes along with long-range magnetic ordering (1/3,1/3). Large quantum fluctuations reduce the Cu2+ moments, likely as a result of the proximity to a phase boundary in the rich magnetic phase diagram of the model. | | | | | | Editors' Suggestion Xuepeng Wang and Debanjan Chowdhury Phys. Rev. B 107, 125157 (2023) – Published 28 March 2023  | A hallmark of a Fermi liquid is a collective excitation associated with fluctuations of the Fermi surface, which evolves into the well-known plasmon in the presence of Coulomb interactions. This paper addresses the fate of the plasmon excitation in non-Fermi liquid metals with a sharply defined Fermi surface, but where long-lived single-electron excitations are absent. The authors use two complementary theoretical techniques to analyze the collective density fluctuations and their decay into the two-particle continuum for three distinct solvable examples of non-Fermi liquids. | | | | | | Editors' Suggestion R. Mirek, M. Furman, M. Król, B. Seredyński, K. Łempicka-Mirek, K. Tyszka, W. Pacuski, M. Matuszewski, J. Szczytko, and B. Piętka Phys. Rev. B 107, 125303 (2023) – Published 10 March 2023  | The authors investigate here the spin polarization of localized exciton-polariton condensates in CdTe-based microcavities doped with magnetic ions. They demonstrate that an effective magnetic field originating from the photonic potential landscape leads to the formation of elliptically polarized condensate. The degree of spin polarization of the condensate depends on the excitation power and polarization of the laser. Based on the magnetic field behavior of the condensate in the presence of magnetic ions, they estimate the polariton-polariton interaction strength in a CdTe system. | | | | | | Editors' Suggestion Rodrick Kuate Defo, Alejandro W. Rodriguez, Efthimios Kaxiras, and Steven L. Richardson Phys. Rev. B 107, 125305 (2023) – Published 13 March 2023  | In calculating the concentrations of the charge states of various defects, the Fermi level is generally assumed to be uniform throughout a semiconductor. The authors establish the timescales involved in thermally driven charge transfer, ultimately refuting the assumption of Fermi-level uniformity on the timescales over which optically detected magnetic resonance (ODMR) spectroscopy experiments are typically performed for NV centers in diamond. Their results reveal the potential for noninvasive determination of defect distances and average defect concentrations through ODMR spectroscopy. | | | | | | Editors' Suggestion Rebecca Engelke, Hyobin Yoo, Stephen Carr, Kevin Xu, Paul Cazeaux, Richard Allen, Andres Mier Valdivia, Mitchell Luskin, Efthimios Kaxiras, Minhyong Kim, Jung Hoon Han, and Philip Kim Phys. Rev. B 107, 125413 (2023) – Published 16 March 2023  | Twisted bilayers of two-dimensional materials contain a moiré superatomic lattice domain that can be bounded by a domain boundary network. The authors show here that the nodes of this network can be considered topological defects. While the nodes in previously studied twisted moiré materials are vortices, the authors discover antivortices formed in strained moiré systems using transmission electron micrographs. This work provides insight into the underlying rules governing moiré structures, inspiring the construction of new types of moiré interfaces. | | | | | | Editors' Suggestion Yuncheng Mao, Daniele Guerci, and Christophe Mora Phys. Rev. B 107, 125423 (2023) – Published 29 March 2023  | Twisted trilayer graphene features a supermoiré pattern on top of two moiré patterns between adjacent layers. Here, the authors have devised a supermoiré effective model for the staircase twisted trilayer graphene, manifesting a gauge field originating from non-Abelian Berry connection acting as a pseudo magnetic field, and a space-dependent anisotropic velocity for the low-energy Dirac electrons. The supermoiré low-energy band structures and profiles of density of states can therefore be accessed by solving the effective model numerically. | | | | | | Editors' Suggestion Letter Yan-Qi Wang, Roman Rausch, Christoph Karrasch, and Joel E. Moore Phys. Rev. B 107, L100301 (2023) – Published 10 March 2023  | The authors propose here a mechanism and an explicit one-dimensional model to realize the linear-in-temperature resistivity that is the hallmark of bad metals. They then verify the behavior with advanced DMRG-type simulations. These results open a new approach to understanding the limits of relaxation generated by local interactions in extended many-body systems. This work should push forward research into understanding some of the most basic questions about transport for 1D and critical systems, which bridge quantum matter and quantum chaos. | | | | | | Editors' Suggestion Letter Y. Venkateswara, Jadupati Nag, S. Shanmukharao Samatham, Akhilesh Kumar Patel, P. D. Babu, Manoj Raama Varma, Jayita Nayak, K. G. Suresh, and Aftab Alam Phys. Rev. B 107, L100401 (2023) – Published 2 March 2023  | FeRhCrSi shows unconventional magnetic and transport properties. It belongs to one of the rare spintronic material classes, namely, spin semimetals. Transport measurements reveal its semimetallic nature, which is further confirmed by ab initio calculations on the partially disordered L21 structure, experimentally synthesized by the authors. The most striking feature is theasymmetric magnetoresistance variation with field at room temperature, clearly revealing spin-valve behavior. Disorder-induced ferrimagnetic regions within the ferromagnetic host are proposed to be the reason for this behavior. Simultaneous observation of spin semimetallic and spin valve features makes this alloy quite interesting both from fundamental and applied perspectives. | | | | | | Editors' Suggestion Letter Zhentao Liu, Zhaochu Luo, Ivan Shorubalko, Christof Vockenhuber, Laura J. Heyderman, Pietro Gambardella, and Aleš Hrabec Phys. Rev. B 107, L100412 (2023) – Published 20 March 2023  | Interlayer couplings are widely used in spintronic devices based on magnetic multilayers. Here, the authors demonstrate instead a strong tunable coupling between adjacent regions of a single ferrimagnetic layer, based on the exchange interaction. They unveil a large lateral exchange bias by spatially patterning the compensation temperature of the ferrimagnet. Furthermore, they show electrical switching of ferrimagnetic domains utilizing the lateral exchange coupling mechanism in combination with spin-orbit torques. | | | | | | Editors' Suggestion Letter Raphael C. Vidal, Giovanni Marini, Lukas Lunczer, Simon Moser, Lena Fürst, Julia Issing, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Charles Gould, Hartmut Buhmann, Wouter Beugeling, Giorgio Sangiovanni, Domenico Di Sante, Gianni Profeta, Laurens W. Molenkamp, Hendrik Bentmann, and Friedrich Reinert Phys. Rev. B 107, L121102 (2023) – Published 14 March 2023  | HgTe is a prime example of a topological material that exhibits a range of topological phases based on its dimensionality and lattice strain. The key to its topological properties lies in the band inversion between the Hg 6s and Te 5p valence levels, leading to the emergence of surface states. In this study, the authors present an in-depth examination of the electronic structure of strained HgTe films using angle-resolved photoelectron spectroscopy and density functional theory. The results offer a direct visualization of the topological band inversion and surface states present in HgTe. | | | | | | Editors' Suggestion Letter Chunli Huang, Tobias M. R. Wolf, Wei Qin, Nemin Wei, Igor V. Blinov, and Allan H. MacDonald Phys. Rev. B 107, L121405 (2023) – Published 17 March 2023  | Lightly doped multilayer graphene surprised researchers with the emergence of superconductivity and magnetism under strong electric displacement fields. The authors interpret the displacement field versus hole-density phase diagram using mean-field theory and experimentally informed band structure. They find that magnetism in these electronic systems is often intertwined with nematic order because of the noncompact Fermi sea topology and fourfold spin-valley degeneracy. | | | | | | | |
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