Physical Review B最新文献

{"title":"Lifetime of triplet excitons in organic LEDs based on thermally activated delayed fluorescence","authors":"G. A. H. Wetzelaer","doi":"10.1103/physrevb.111.l241201","DOIUrl":"https://doi.org/10.1103/physrevb.111.l241201","url":null,"abstract":"Organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) are currently limited by their operational stability and a decreased efficiency at high brightness, both of which are strongly related to the interactions between triplet excitons and other quasiparticles. Here, an expression for the lifetime of triplet excitons in TADF OLEDs is derived, which correlates with the efficiency roll-off. The triplet lifetime in a TADF OLED intriguingly can be well approximated by the delayed-fluorescence lifetime of the TADF emitter, enabling facile quantification of the triplet population in a working OLED for investigating triplet-related loss processes, such as the efficiency roll-off and degradation. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"1 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-stage relaxation of operators through domain wall and magnon dynamics","authors":"Cheryne Jonay, Cathy Li, Tianci Zhou","doi":"10.1103/physrevb.111.224304","DOIUrl":"https://doi.org/10.1103/physrevb.111.224304","url":null,"abstract":"The out-of-time-ordered correlator (OTOC) is a popular probe for quantum information spreading and thermalization. In systems with local interactions, the OTOC defines a characteristic butterfly light cone that separates a regime unperturbed by chaos from one where time-evolved operators and the OTOC approach equilibrium. This relaxation has been shown to proceed in two stages. The first stage exhibits an extensive timescale and a decay rate known as the “phantom eigenvalue”, which is slower than the gap of the transfer matrix. In this paper, we investigate the two-stage relaxation of the OTOC towards its equilibrium value in various local quantum circuits. We apply a systematic framework based on an emergent statistical model, where the dynamics of two single-particle modes—a domain wall and a magnon—govern the decay rates. We show that a configuration with coexisting domain wall and magnon modes generates the phantom rate in the first stage, while competition between these two modes determines the second stage. We also examine this relaxation within the operator cluster picture. The magnon modes translate into a bound state of clusters, and the domain wall into a random operator, giving consistent rates. Finally, we extend our findings from random-in-time circuits to a broad class of Floquet models. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"21 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144252027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stevens operator class of exactly solvable one-dimensional spin models","authors":"A. A. Zvyagin, V. V. Slavin","doi":"10.1103/physrevb.111.214417","DOIUrl":"https://doi.org/10.1103/physrevb.111.214417","url":null,"abstract":"The new class of exactly solvable models of one-dimensional spin chains is found. Interactions of spins with crystalline electric fields (CEF) and spin-spin coupling between neighboring sites are taken into account for those models. Spin-spin coupling includes higher-order spin operators (the Stevens operators) and describes the interaction between z</a:mi>th</a:mi></a:mrow></a:math> components of the spins. We show that essential parts of the Hamiltonians of these models can be written in terms of exactly solvable transverse field Ising model (TFIM), in which certain combinations of the parameters of spin-spin interactions play the role of the TFIM exchange constant, and components of the CEFs play the role of external transverse magnetic field of the TFIM. The obtained results are valid for any values of spin (or total moments for rare-earth ions) and for the wide class of CEFs. The requirement for the exact solvability is that the space of single spin states should be split by the CEF into the subspaces with dimensions <b:math xmlns:b=\"http://www.w3.org/1998/Math/MathML\"><b:mrow><b:mo>≤</b:mo><b:mn>2</b:mn></b:mrow></b:math> (i.e., the only singlets and doublets are allowed). Cases of integer and half-integer spins are considered. For finite-size chains with integer spins and open ends we show numerically that energy spectra always contain the states whose energies do not depend on the CEF (the magnetic field for the TFIM). The energies (per spin) of these states decay as <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\"><c:msup><c:mi>L</c:mi><c:mrow><c:mo>−</c:mo><c:mn>1</c:mn></c:mrow></c:msup></c:math>, where <d:math xmlns:d=\"http://www.w3.org/1998/Math/MathML\"><d:mi>L</d:mi></d:math> is the chain length. This behavior qualitatively distinguishes these states from known Majorana edge states and strong zero modes, where the energy decreases exponentially in <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\"><e:mi>L</e:mi></e:math>. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"7 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144252026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vortex frequency locking and Shapiro steps in superconductor open nanotubes","authors":"Igor Bogush, Vladimir M. Fomin, Oleksandr V. Dobrovolskiy","doi":"10.1103/physrevb.111.214510","DOIUrl":"https://doi.org/10.1103/physrevb.111.214510","url":null,"abstract":"The movement of magnetic flux quanta (Abrikosov vortices) in superconductors leads to dissipation and is influenced by various ordering effects arising from vortex-vortex, vortex-defect, and vortex-edge interactions. Under combined dc and ac stimuli, when the distance traveled by fluxons during an ac cycle corresponds to an integer multiple of the vortex lattice period, the superconductor's current-voltage (I</a:mi>−</a:mtext>V</a:mi></a:mrow></a:math>) curve displays synchronization (Shapiro) steps. However, in planar constrictions, frequency-locking effects rely on a perfectly ordered vortex lattice and are typically observed when periodic vortex pinning arrays dominate over intrinsic uncorrelated disorder. Here, we propose 3D superconducting open nanotubes as systems free of periodic disorder, where the <b:math xmlns:b=\"http://www.w3.org/1998/Math/MathML\"><b:mrow><b:mi>I</b:mi><b:mtext>−</b:mtext><b:mi>V</b:mi></b:mrow></b:math> curves are expected to display pronounced Shapiro steps. Using the time-dependent Ginzburg-Landau equation, we attribute the predicted effect to a reduction in the dimensionality of vortex motion. Namely, rolling a planar film into a tube causes the 2D vortex array, which initially moves throughout the film, to evolve into quasi-1D vortex chains that are restricted to areas where the normal component of the magnetic field is near its maximum. The discussed effects are relevant for superconducting devices, where vortex nucleation frequency and voltage stabilization by an external ac stimulus can enhance their operation. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"43 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144252024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theory for tunnel magnetoresistance oscillation","authors":"Keisuke Masuda, Thomas Scheike, Hiroaki Sukegawa, Yusuke Kozuka, Seiji Mitani, Yoshio Miura","doi":"10.1103/physrevb.111.l220406","DOIUrl":"https://doi.org/10.1103/physrevb.111.l220406","url":null,"abstract":"The universal oscillation of the tunnel magnetoresistance (TMR) ratio as a function of the insulating barrier thickness in crystalline magnetic tunnel junctions (MTJs) is a long-standing unsolved problem in condensed matter physics. To explain this, we here introduce a superposition of wave functions with opposite spins and different Fermi momenta, based on the fact that spin-flip scattering near the interface provides a hybridization between majority- and minority-spin states. In a typical Fe/MgO/Fe MTJ, we solve the tunneling problem and show that the TMR ratio oscillates with a period of ∼</a:mo>3</a:mn></a:mrow></a:math>Å by varying the MgO thickness, consistent with previous and present experimental observations. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"22 Suppl 1 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144252025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variationally optimizing infinite projected entangled-pair states at large bond dimensions: A split corner transfer matrix renormalization group approach","authors":"Jan Naumann, Erik L. Weerda, Jens Eisert, Matteo Rizzi, Philipp Schmoll","doi":"10.1103/physrevb.111.235116","DOIUrl":"https://doi.org/10.1103/physrevb.111.235116","url":null,"abstract":"Projected entangled-pair states (PEPS) have become a powerful tool for studying quantum many-body systems in the condensed matter and quantum materials context, particularly with advances in variational energy optimization methods. A key challenge within this framework is the computational cost associated with the contraction of the two-dimensional lattice, crucial for calculating state vector norms and expectation values. The conventional approach, using the corner transfer matrix renormalization group (CTMRG), involves combining two tensor network layers, resulting in significant time and memory demands. In this work, we introduce an alternative split-CTMRG algorithm, which maintains separate PEPS layers and leverages modified environment tensors, reducing computational complexity while preserving accuracy. Benchmarks on quantum lattice models demonstrate substantial speedups for variational energy optimization, rendering this method valuable for large-scale PEPS simulations. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"36 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rotational magnetoelastic interactions in the Dzyaloshinskii-Moriya magnet Ba2CuGe2O7","authors":"J. Sourd, T. Kotte, P. Wild, S. Mühlbauer, J. Wosnitza, S. Zherlitsyn","doi":"10.1103/physrevb.111.224411","DOIUrl":"https://doi.org/10.1103/physrevb.111.224411","url":null,"abstract":"We report the magnetoelastic properties of a Ba</a:mi>2</a:mn></a:msub>CuGe</a:mi>2</a:mn></a:msub>O</a:mi>7</a:mn></a:msub></a:mrow></a:math> single crystal at low temperatures under a magnetic field applied along the crystallographic [001] axis. Our results extend to low temperatures, the <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\"><c:mrow><c:mi>H</c:mi><c:mo>−</c:mo><c:mi>T</c:mi></c:mrow></c:math> phase diagram determined for this compound by neutron scattering. Furthermore, we observe that specific elastic modes are more sensitive to the various magnetic transitions. In particular, we observe an unusual coupling between the transverse acoustic mode in the (001) plane and the cycloidal order at low field, which suggests a spin-strain mechanism originating from Dzyaloshinskii-Moriya interaction in this compound. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"10 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144237145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anisotropic supercurrent suppression and revivals in a graphene-based Josephson junction under in-plane magnetic fields","authors":"Philipp Schmidt, Katarina Stanojević, Kenji Watanabe, Takashi Taniguchi, Bernd Beschoten, Vincent Mourik, Christoph Stampfer","doi":"10.1103/physrevb.111.245301","DOIUrl":"https://doi.org/10.1103/physrevb.111.245301","url":null,"abstract":"We report on a tunable Josephson junction formed by a bilayer graphene ribbon encapsulated in WSe</a:mi>2</a:mn></a:msub></a:math> with superconducting niobium contacts. We characterize the junction by measurements of the magnetic field–induced interference pattern and the AC Josephson effect manifested as Shapiro steps, examining current-dependent hysteresis and junction dynamics. The latter can be tuned by temperature, gate voltage, and magnetic field. Finally, we examine the evolution of the supercurrent when subjected to in-plane magnetic fields. Notably, we observe strong anisotropy in the supercurrent with respect to the orientation of the in-plane magnetic field. When the field is parallel to the current direction, the supercurrent is suppressed and shows revivals with increasing magnetic field, whereas it remains almost unaffected when the field is oriented in a perpendicular direction. We suggest that this anisotropy is caused by the dependence of supercurrent interference on the junction geometry. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"21 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermodynamic properties of a superconductor interfaced with an altermagnet","authors":"Simran Chourasia, Aleksandr Svetogorov, Akashdeep Kamra, Wolfgang Belzig","doi":"10.1103/physrevb.111.224503","DOIUrl":"https://doi.org/10.1103/physrevb.111.224503","url":null,"abstract":"Recently introduced magnetic materials called altermagnets (AM) feature zero net magnetization but a momentum-dependent magnetic exchange field, which can have intriguing implications when combined with superconductivity. In our work, we use the quasiclassical framework to study the effects of such a material on a conventional superconductor (S) in an AM/S bilayer. We discuss the superconducting phase diagram and heat capacity of AM/S while making a comparison with a ferromagnet-superconductor bilayer. Furthermore, we examine the density of states and analyze the system's response to an external magnetic field. We illustrate the anisotropy of spin susceptibility and magnetization of AM/S by considering an external field in the in-plane and out-of-plane directions, thereby facilitating the scope of experimental detection and characterization of an AM in an AM/S hybrid system. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"85 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144228605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Competing automorphisms and disordered Floquet codes","authors":"Cory T. Aitchison, Benjamin Béri","doi":"10.1103/physrevb.111.235112","DOIUrl":"https://doi.org/10.1103/physrevb.111.235112","url":null,"abstract":"Topological order is a promising basis for quantum error correction, a key milestone towards large-scale quantum computing. Floquet codes provide a dynamical scheme for this while also exhibiting Floquet-enriched topological order where anyons periodically undergo a measurement-induced automorphism that acts uniformly in space. We study disordered Floquet codes where automorphisms have a spatiotemporally heterogeneous distribution: the automorphisms “compete.” We characterize the effect of this competition, showing how key features of the purification dynamics of mixed code states can be inferred from anyon and automorphism properties for any Abelian topological order. This perspective can explain the preservation or measurement of logical information in a dynamic automorphism (DA) code when subjected to a noise model of missing measurements. We demonstrate this using a DA color code with perturbed measurement sequences. The framework of competing automorphisms captures essential features of Floquet codes and robustness to noise, and may elucidate key mechanisms involving topological order, automorphisms, and fault tolerance. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"34 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144228607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}