Physical Review X最新文献

{"title":"Theoretical Lower Limit of Coercive Field in Ferroelectric Hafnia","authors":"Jiyuan Yang, Jing Wu, Jingxuan Li, Chao Zhou, Yang Sun, Zuhuang Chen, Shi Liu","doi":"10.1103/physrevx.15.021042","DOIUrl":"https://doi.org/10.1103/physrevx.15.021042","url":null,"abstract":"The high coercive field (E</a:mi>c</a:mi></a:msub></a:math>) of hafnia-based ferroelectrics presents a major obstacle to their applications. The ferroelectric switching mechanisms in hafnia that dictate <d:math xmlns:d=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><d:msub><d:mi mathvariant=\"script\">E</d:mi><d:mi>c</d:mi></d:msub></d:math>, especially those related to domain nucleation in the nucleation-limited-switching (NLS) model and domain-wall motion in the Kolmogorov-Avrami-Ishibashi (KAI) model, have remained elusive. We develop a deep-learning-assisted multiscale approach, incorporating atomistic insights into the critical nucleus, to predict both NLS- and KAI-type coercive fields. The theoretical NLS-type <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:msub><g:mi mathvariant=\"script\">E</g:mi><g:mi>c</g:mi></g:msub></g:math> values agree with previous experimental results as well as our own measurements and also exhibit the correct thickness scaling for films between 3 and 20 nm. Combined theoretical and experimental investigations reveal that the giant <j:math xmlns:j=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><j:msub><j:mi mathvariant=\"script\">E</j:mi><j:mi>c</j:mi></j:msub></j:math> in hafnia-based ferroelectrics arises from the ultrathin geometry, which confines switching to the NLS mechanism. We predict that the theoretical lower limit for KAI-type <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><m:msub><m:mi mathvariant=\"script\">E</m:mi><m:mi>c</m:mi></m:msub></m:math> is <p:math xmlns:p=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><p:mrow><p:mn>0.1</p:mn><p:mtext> </p:mtext><p:mtext> </p:mtext><p:mi>MV</p:mi><p:mo>/</p:mo><p:mi>cm</p:mi></p:mrow></p:math> arising from mobile domain walls. The activation of KAI-type switching to achieve lower <r:math xmlns:r=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><r:msub><r:mi mathvariant=\"script\">E</r:mi><r:mi>c</r:mi></r:msub></r:math> is supported by our experimental demonstration of a low coercive field of <u:math xmlns:u=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><u:mrow><u:mn>1</u:mn><u:mtext> </u:mtext><u:mtext> </u:mtext><u:mi>MV</u:mi><u:mo>/</u:mo><u:mi>cm</u:mi></u:mrow></u:math> in 60 nm ferroelectric <w:math xmlns:w=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><w:mrow><w:mo stretchy=\"false\">(</w:mo><w:mrow><w:msub><w:mrow><w:mi>HfO</w:mi></w:mrow><w:mrow><w:mn>2</w:mn></w:mrow></w:msub></w:mrow><w:msub><w:mrow><w:mo stretchy=\"false\">)</w:mo></w:mrow><w:mrow><w:mi>n</w:mi></w:mrow></w:msub><w:mo>/</w:mo><w:mo stretchy=\"false\">(</w:mo><w:mrow><w:msub><w:mrow><w:mi>ZrO</w:mi></w:mrow><w:mrow><w:mn>2</w:mn></w:mrow></w:msub></w:mrow><w:msub><w:mrow><w:mo stretchy=\"false\">)</w:mo></w:mrow><w:mrow><w:mi>n</w:mi></w:mrow></w:msub></w:mrow></w:math> (<cb:math xmlns:cb=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><cb:mi>n</cb:mi><cb:mo>=</cb:mo><cb:mn>3</cb:mn></cb:math> unit cel","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"25 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143915437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Topological Meron-Antimeron Domain Walls and Skyrmions in a Low-Symmetry System","authors":"Reiner Brüning, Levente Rózsa, Roberto Lo Conte, André Kubetzka, Roland Wiesendanger, Kirsten von Bergmann","doi":"10.1103/physrevx.15.021041","DOIUrl":"https://doi.org/10.1103/physrevx.15.021041","url":null,"abstract":"The generation of topologically nontrivial magnetic configurations has been a pivotal topic in both basic and applied nanomagnetism research. Localized noncoplanar magnetic defects such as skyrmions or merons were found to interact strongly with currents, making them interesting candidates for future spintronics applications. So far, mostly systems with a high rotational symmetry have been investigated where skyrmions were axially symmetric. Here, we study a low-symmetry system by spin-polarized scanning tunneling microscopy and an atomistic spin model using parameters based on first-principles calculations. We demonstrate how a delicate balance between energy terms generates both topologically trivial and nontrivial domain walls, depending on their nonequivalent crystallographic direction. The topological walls consist of alternating merons and antimerons, and the topological charge is 1 for every 6-nm length of the wall. The incorporation of holes in the films facilitates the transition from an in-plane ferromagnetic ground state to a spin-spiral state. Both domain walls and spirals transition into isolated elongated magnetic skyrmions in applied magnetic fields. These findings establish low-symmetry systems as a versatile platform for spin-texture engineering. <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":20161,"journal":{"name":"Physical Review X","volume":"50 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143915436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Realistic Ab Initio Predictions of Excimer Behavior under Collective Light-Matter Strong Coupling","authors":"Matteo Castagnola, Marcus T. Lexander, Henrik Koch","doi":"10.1103/physrevx.15.021040","DOIUrl":"https://doi.org/10.1103/physrevx.15.021040","url":null,"abstract":"Experiments show that light-matter strong coupling affects chemical properties, though the underlying mechanism remains unclear. A major challenge is to perform reliable and affordable simulation of molecular behavior when many molecules are collectively coupled to the same optical mode. This paper presents an quantum electrodynamics coupled cluster method for the collective strong coupling regime. The model describes electronic and electron-photon correlation within a molecular subsystem, while a simplified description of the collective polaritonic excitations allows for a realistic microscopic light-matter coupling. The developed framework provides a computationally tractable route to accurately simulate a molecule in a collective environment, which is unfeasible when several molecules are treated explicitly. We investigate the properties of the argon dimer under strong light-matter coupling. In the single-molecule regime (large light-matter coupling), the potential energies are substantially modified, weakening the excimer bond. In contrast, in the collective regime (small light-matter coupling, large number of molecules), the ground state potential energy surface and the first vibrational levels of the excited state do not change significantly. However, collective strong coupling produces an abrupt transition in the vibrational landscape of the excimer, causing higher vibrational levels to behave similarly to the vibrations in the ground state. We expect the excimer formation to be inhibited by light-matter strong coupling and conclude that chemical properties are altered via distinct mechanisms in the collective and single-molecule regimes. We also discuss fundamental aspects of polaritonic chemistry, such as resonance conditions and sudden changes of the molecular properties when a critical collective coupling strength is achieved. <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":20161,"journal":{"name":"Physical Review X","volume":"11 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143909768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Coherent Phonons and Quasiparticle Renormalization in Semimetals from First Principles","authors":"Christoph Emeis, Stephan Jauernik, Sunil Dahiya, Yiming Pan, Carl E. Jensen, Petra Hein, Michael Bauer, Fabio Caruso","doi":"10.1103/physrevx.15.021039","DOIUrl":"https://doi.org/10.1103/physrevx.15.021039","url":null,"abstract":"Coherent phonons, light-induced coherent lattice vibrations in solids, provide a powerful route to engineer structural and electronic degrees of freedom using light. In this manuscript, we formulate an theory of the displacive excitation of coherent phonons (DECP), the primary mechanism for light-induced structural control in semimetals. Our study—based on the simulations of the ultrafast electron and coherent-phonon dynamics in the presence of electron-phonon interactions—establishes a predictive computational framework for describing the emergence of light-induced structural changes and the ensuing transient band-structure renormalization arising from the DECP mechanism. We validate this framework via a combined theoretical and experimental investigation of coherent phonons in the elemental semimetal antimony. Via a Fourier analysis of time- and angle-resolved photoemission spectroscopy measurements, we retrieve information about transient spectral features and quasiparticle renormalization arising from the coherent A</a:mi>1</a:mn>g</a:mi></a:mrow></a:msub></a:math> phonon as a function of momentum, energy, time, and fluence. The qualitative and quantitative agreement between experiment and theory corroborates the first-principles approach formulated in this study. We further apply this formalism to investigate the coherent-phonon dynamics in the topological Weyl semimetal -<c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:msub><c:mrow><c:mi>WTe</c:mi></c:mrow><c:mn>2</c:mn></c:msub></c:mrow></c:math>. Besides reproducing the entire spectrum of coherent phonons observed in experiments, our simulations clearly indicate that the shear <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:msub><e:mi>A</e:mi><e:mrow><e:mn>1</e:mn><e:mi>g</e:mi></e:mrow></e:msub></e:math> mode—the mode orchestrating a light-induced phase transition in -<g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mrow><g:msub><g:mrow><g:mi>WTe</g:mi></g:mrow><g:mn>2</g:mn></g:msub></g:mrow></g:math>—is strongly driven by the DECP mechanism and, thus, provide a conclusive explanation for the driving mechanism underpinning the phase transition. Besides advancing the fundamental understanding of electron-phonon interactions mediated by coherent phonons, this study opens new opportunities for predictively engineering structural and electronic degrees of freedom in semimetals via the DECP mechanism. <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":20161,"journal":{"name":"Physical Review X","volume":"20 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143909724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Automated Discovery of Coupled-Mode Setups","authors":"Jonas Landgraf, Vittorio Peano, Florian Marquardt","doi":"10.1103/physrevx.15.021038","DOIUrl":"https://doi.org/10.1103/physrevx.15.021038","url":null,"abstract":"In optics and photonics, a small number of building blocks—like resonators, waveguides, arbitrary couplings, and parametric interactions—allow the design of a broad variety of devices and functionalities, distinguished by their scattering properties. These devices include transducers, amplifiers, and nonreciprocal devices, like isolators or circulators. Usually, the design of such a system is handcrafted by an experienced scientist in a time-consuming process, where it remains uncertain whether the simplest possibility has indeed been found. In our work, we develop the discovery algorithm , which automates this challenge. By optimizing the continuous and discrete system properties, our automated search identifies the minimal resources required to realize the requested scattering behavior. In the spirit of artificial scientific discovery, it produces a complete list of interpretable solutions and leads to generalizable insights, as we illustrate in several examples. opens the door towards the automated discovery of scattering setups for photonics, microwaves, and optomechanics, with possible future extensions to periodic structures, sensing, and electronic devices. <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":20161,"journal":{"name":"Physical Review X","volume":"22 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143901185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Experimental Mode-Pairing Quantum Key Distribution Surpassing the Repeaterless Bound","authors":"Likang Zhang, Wei Li, Jiawei Pan, Yichen Lu, Wenwen Li, Zheng-Ping Li, Yizhi Huang, Xiongfeng Ma, Feihu Xu, Jian-Wei Pan","doi":"10.1103/physrevx.15.021037","DOIUrl":"https://doi.org/10.1103/physrevx.15.021037","url":null,"abstract":"Quantum key distribution (QKD) provides information-theoretic security for communication. The mode-pairing (MP) protocol emerges as a promising solution for long-distance QKD by eliminating the need for a global phase reference while maintaining the repeaterlike rate-loss scaling. Recent implementations have demonstrated its potential, but they either rely on costly ultrastable lasers or struggle with phase fluctuations from commercial lasers, particularly over long distances. As a result, surpassing the repeaterless bound with a practical system remains a challenge. In this work, we demonstrate a practical high-performance MP-QKD system using commercial lasers. To address phase fluctuations, we propose a frequency-tracking scheme based on fast Fourier transformation, enabling us to extend the pairing length to 2</a:mn>×</a:mo>10</a:mn>5</a:mn></a:msup></a:math> pulses (<c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:mn>160</c:mn><c:mtext> </c:mtext><c:mtext> </c:mtext><c:mi mathvariant=\"normal\">μ</c:mi><c:mi mathvariant=\"normal\">s</c:mi></c:mrow></c:math>). We propose a model to carefully analyze the phase noise and optimize the system parameters. Our system achieves an optimal secret key rate of <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mrow><g:mn>47.8</g:mn><g:mtext> </g:mtext><g:mtext> </g:mtext><g:mi>bit</g:mi><g:mo>/</g:mo><g:mi mathvariant=\"normal\">s</g:mi></g:mrow></g:math> over 403 km of standard fiber (76.5 dB loss), exceeding the repeaterless bound by a factor of 2.92. Furthermore, we compare MP-QKD and twin-field QKD under various practical conditions and clarify the distinct application scenarios of the two protocols. These results confirm the feasibility of MP-QKD using cost-effective commercial technologies, paving the way for scalable quantum communication networks. <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":20161,"journal":{"name":"Physical Review X","volume":"44 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143901192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Modular Autonomous Virtualization System for Two-Dimensional Semiconductor Quantum Dot Arrays","authors":"Anantha S. Rao, Donovan Buterakos, Barnaby van Straaten, Valentin John, Cécile X. Yu, Stefan D. Oosterhout, Lucas Stehouwer, Giordano Scappucci, Menno Veldhorst, Francesco Borsoi, Justyna P. Zwolak","doi":"10.1103/physrevx.15.021034","DOIUrl":"https://doi.org/10.1103/physrevx.15.021034","url":null,"abstract":"Arrays of gate-defined semiconductor quantum dots are among the leading candidates for building scalable quantum processors. High-fidelity initialization, control, and readout of spin qubit registers require exquisite and targeted control over key Hamiltonian parameters that define the electrostatic environment. However, due to the tight gate pitch, capacitive crosstalk between gates hinders independent tuning of chemical potentials and interdot couplings. While virtual gates offer a practical solution, determining all the required cross-capacitance matrices accurately and efficiently in large quantum dot registers is an open challenge. Here, we establish a modular automated virtualization system (MAViS)—a general and modular framework for autonomously constructing a complete stack of multilayer virtual gates in real time. Our method employs machine learning techniques to rapidly extract features from two-dimensional charge stability diagrams. We then utilize computer vision and regression models to self-consistently determine all relative capacitive couplings necessary for virtualizing plunger and barrier gates in both low- and high-tunnel-coupling regimes. Using MAViS, we successfully demonstrate accurate virtualization of a dense two-dimensional array comprising ten quantum dots defined in a high-quality Ge</a:mi>/</a:mo>SiGe</a:mi></a:mrow></a:math> heterostructure. Our work offers an elegant and practical solution for the efficient control of large-scale semiconductor quantum dot systems. <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":20161,"journal":{"name":"Physical Review X","volume":"95 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Topological Rigidity and Non-Abelian Defect Junctions in Chiral Nematic Systems with Effective Biaxial Symmetry","authors":"Jin-Sheng Wu, Roberto Abril Valenzuela, Mark J. Bowick, Ivan I. Smalyukh","doi":"10.1103/physrevx.15.021036","DOIUrl":"https://doi.org/10.1103/physrevx.15.021036","url":null,"abstract":"We study topologically stable defect structures in systems where the defect line classification in three dimensions and associated algebra of interactions (the fundamental group) are governed by the non-Abelian eight-element group, the quaternions Q</a:mi>8</a:mn></a:msub></a:math>. The non-Abelian character of the defect algebra leads to a topological rigidity of bound defect pairs, and trivalent junctions which are the building blocks of multijunction trivalent networks. We realize such structures in laboratory chiral nematics and analyze their behavior analytically, along with numerical modeling. <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":20161,"journal":{"name":"Physical Review X","volume":"3 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Strongly Interacting, Two-Dimensional, Dipolar Spin Ensembles in (111)-Oriented Diamond","authors":"Lillian B. Hughes, Simon A. Meynell, Weijie Wu, Shreyas Parthasarathy, Lingjie Chen, Zhiran Zhang, Zilin Wang, Emily J. Davis, Kunal Mukherjee, Norman Y. Yao, Ania C. Bleszynski Jayich","doi":"10.1103/physrevx.15.021035","DOIUrl":"https://doi.org/10.1103/physrevx.15.021035","url":null,"abstract":"Systems of spins with strong dipolar interactions and controlled dimensionality enable new explorations in quantum sensing and simulation. In this work, we investigate the creation of strong dipolar interactions in a two-dimensional ensemble of nitrogen-vacancy (NV) centers generated via plasma-enhanced chemical vapor deposition on (111)-oriented diamond substrates. We find that diamond growth on the (111) plane yields high incorporation of spins, both nitrogen and NV centers, where the density of the latter is tunable via the miscut of the diamond substrate. Our process allows us to form dense, preferentially aligned, 2D NV ensembles with volume-normalized ac sensitivity down to η</a:mi></a:mrow>ac</a:mi></a:mrow></a:msub>=</a:mo>810</a:mn></a:mtext></a:mtext>pT</a:mi></a:mtext>μ</a:mi>m</a:mi></a:mrow>3</a:mn>/</a:mo>2</a:mn></a:mrow></a:msup></a:mtext>Hz</a:mi></a:mrow>−</a:mo>1</a:mn>/</a:mo>2</a:mn></a:mrow></a:msup></a:mrow></a:math>. Furthermore, we show that (111) affords maximally positive dipolar interactions among a 2D NV ensemble, which is crucial for leveraging dipolar-driven entanglement schemes and exploring new interacting spin physics. <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":20161,"journal":{"name":"Physical Review X","volume":"29 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Single-Crystal Diffuse Neutron Scattering Study of the Dipole-Octupole Quantum Spin-Ice Candidate Ce2Zr2O7 : No Apparent Octupolar Correlations Above T=0.05 K","authors":"E. M. Smith, R. Schäfer, J. Dudemaine, B. Placke, B. Yuan, Z. Morgan, F. Ye, R. Moessner, O. Benton, A. D. Bianchi, B. D. Gaulin","doi":"10.1103/physrevx.15.021033","DOIUrl":"https://doi.org/10.1103/physrevx.15.021033","url":null,"abstract":"The insulating magnetic pyrochlore Ce</a:mi></a:mrow>2</a:mn></a:mrow></a:msub></a:mrow>Zr</a:mi></a:mrow>2</a:mn></a:mrow></a:msub>O</a:mi></a:mrow>7</a:mn></a:mrow></a:msub></a:mrow></a:math> has gained attention as a quantum spin-ice candidate with dipole-octupole character that arises from the crystal-electric-field ground-state doublet for the <d:math xmlns:d=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><d:mrow><d:msup><d:mrow><d:mi>Ce</d:mi></d:mrow><d:mrow><d:mn>3</d:mn><d:mo>+</d:mo></d:mrow></d:msup></d:mrow></d:math> Kramers ion. This dipole-octupole character permits both spin-ice phases based on magnetic dipoles and those based on more-exotic octupoles. This work reports low-temperature neutron diffraction measurements on single-crystal <f:math xmlns:f=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><f:mrow><f:mrow><f:msub><f:mrow><f:mi>Ce</f:mi></f:mrow><f:mrow><f:mn>2</f:mn></f:mrow></f:msub></f:mrow><f:msub><f:mrow><f:mi>Zr</f:mi></f:mrow><f:mrow><f:mn>2</f:mn></f:mrow></f:msub><f:msub><f:mrow><f:mi mathvariant=\"normal\">O</f:mi></f:mrow><f:mrow><f:mn>7</f:mn></f:mrow></f:msub></f:mrow></f:math> with <i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><i:mi>Q</i:mi></i:math> coverage both at low <k:math xmlns:k=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><k:mi>Q</k:mi></k:math>, where the magnetic form factor for dipoles is near maximal, and at high <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><m:mi>Q</m:mi></m:math>, covering the region where the magnetic form factor for <o:math xmlns:o=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><o:mrow><o:msup><o:mrow><o:mi>Ce</o:mi></o:mrow><o:mrow><o:mn>3</o:mn><o:mo>+</o:mo></o:mrow></o:msup></o:mrow></o:math> octupoles is near maximal. This study was motivated by recent powder neutron diffraction studies of other Ce-based dipole-octupole pyrochlores, <q:math xmlns:q=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><q:mrow><q:mrow><q:msub><q:mrow><q:mi>Ce</q:mi></q:mrow><q:mrow><q:mn>2</q:mn></q:mrow></q:msub></q:mrow><q:msub><q:mrow><q:mi>Sn</q:mi></q:mrow><q:mrow><q:mn>2</q:mn></q:mrow></q:msub><q:msub><q:mrow><q:mi mathvariant=\"normal\">O</q:mi></q:mrow><q:mrow><q:mn>7</q:mn></q:mrow></q:msub></q:mrow></q:math> and <t:math xmlns:t=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><t:mrow><t:mrow><t:msub><t:mrow><t:mi>Ce</t:mi></t:mrow><t:mrow><t:mn>2</t:mn></t:mrow></t:msub></t:mrow><t:msub><t:mrow><t:mi>Hf</t:mi></t:mrow><t:mrow><t:mn>2</t:mn></t:mrow></t:msub><t:msub><t:mrow><t:mi mathvariant=\"normal\">O</t:mi></t:mrow><t:mrow><t:mn>7</t:mn></t:mrow></t:msub></t:mrow></t:math>, which each showed temperature-dependent diffuse diffraction at high <w:math xmlns:w=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><w:mi>Q</w:mi></w:math>, interpreted as arising from octupolar correlations. Our measurements use an optimized single-crystal diffuse scattering instrument that allows us to screen against strong","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"42 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}