Pub Date : 2026-02-11DOI: 10.1038/s41535-026-00854-y
Jonathan Gaudet, Dalmau Reig-i-Plessis, Bogeng Wen, Thomas J. Hicken, Jonas A. Krieger, Jan Peter Embs, Hubertus Luetkens, Adam A. Aczel, Stuart A. Calder, Matthew B. Stone, Hae-Young Kee, Alannah M. Hallas
We investigate the magnetic ground state of CuNdO2, which is a delafossite with a triangular lattice of magnetic Nd3+ ions that are well separated by non-magnetic Cu spacer layers. From inelastic neutron scattering measurements of the crystal electric field, we determine the strong Ising character of the pseudo-spin 1/2 Nd3+ moments. Magnetic susceptibility and heat capacity measurements reveal the onset of long-range antiferromagnetic order at TN = 0.78 K. While the magnetic transition is definitively observed with muon spin relaxation, accompanied by the formation of a weakly dispersing spin wave excitation, no dipole-ordered moment is detected with neutron diffraction. We show that the apparent absence of a dipolar ordered moment is a consequence of the dominant Ising character of the antiferromagnetically coupled Nd3+ moments, which experience extreme frustration on the triangular lattice. Consequently, the frustration in CuNdO2 is relieved through in-plane ordering of the substantially smaller perpendicular component of the Nd3+ moments into a 120° structure, with a nearly vanishing ordered moment.
{"title":"Vanishing ordered moment in the frustrated triangular lattice antiferromagnet CuNdO2","authors":"Jonathan Gaudet, Dalmau Reig-i-Plessis, Bogeng Wen, Thomas J. Hicken, Jonas A. Krieger, Jan Peter Embs, Hubertus Luetkens, Adam A. Aczel, Stuart A. Calder, Matthew B. Stone, Hae-Young Kee, Alannah M. Hallas","doi":"10.1038/s41535-026-00854-y","DOIUrl":"https://doi.org/10.1038/s41535-026-00854-y","url":null,"abstract":"We investigate the magnetic ground state of CuNdO2, which is a delafossite with a triangular lattice of magnetic Nd3+ ions that are well separated by non-magnetic Cu spacer layers. From inelastic neutron scattering measurements of the crystal electric field, we determine the strong Ising character of the pseudo-spin 1/2 Nd3+ moments. Magnetic susceptibility and heat capacity measurements reveal the onset of long-range antiferromagnetic order at TN = 0.78 K. While the magnetic transition is definitively observed with muon spin relaxation, accompanied by the formation of a weakly dispersing spin wave excitation, no dipole-ordered moment is detected with neutron diffraction. We show that the apparent absence of a dipolar ordered moment is a consequence of the dominant Ising character of the antiferromagnetically coupled Nd3+ moments, which experience extreme frustration on the triangular lattice. Consequently, the frustration in CuNdO2 is relieved through in-plane ordering of the substantially smaller perpendicular component of the Nd3+ moments into a 120° structure, with a nearly vanishing ordered moment.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"95 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146152278","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}
Pub Date : 2026-02-10DOI: 10.1038/s41535-026-00862-y
Jinhao Zhang, Zhanshan Sun, Jiawei Yao, Fengting Zhao, Yi Lin, Di Sang, Kai Yang, Qiang An, Yunqi Fu
Rydberg atomic receiver holds distinctive advantages of ultra-wide operating bandwidth and inherently high sensitivity in electric field measurement1, in particular, it promises unique superiority of miniaturization for low-frequency especially kHz-band signals, which hold pivotal value in applications such as long-range navigation, ground-penetrating radar, and underwater communication. However, the capability of kHz atomic receivers remains severely constrained by the shielding effects of adsorbed alkali metal atoms. Here, we propose a conceptually new self-dressing kHz signal measurement paradigm by converting the undesired coupling-laser-induced DC field to an atomic dressing, and deftly building atomic superheterodyne inside the sapphire vapor cell, which is prepared to adequately suppress the low-frequency shielding through resistivity manipulation engineering. Further, we realize strengthened interaction between the atoms and kHz field by localized enhancement of the incident signals, and finally achieve an ultrahigh sensitivity of 13.5 nV/cm/Hz1/2 at 100 kHz. This architecture represents a significant advance, with the potential to greatly accelerate the practical applications of Rydberg atomic receivers in kHz-band detection, communication, and related fields.
{"title":"Self-dressing Rydberg atomic receiver based on laser-induced DC field","authors":"Jinhao Zhang, Zhanshan Sun, Jiawei Yao, Fengting Zhao, Yi Lin, Di Sang, Kai Yang, Qiang An, Yunqi Fu","doi":"10.1038/s41535-026-00862-y","DOIUrl":"https://doi.org/10.1038/s41535-026-00862-y","url":null,"abstract":"Rydberg atomic receiver holds distinctive advantages of ultra-wide operating bandwidth and inherently high sensitivity in electric field measurement1, in particular, it promises unique superiority of miniaturization for low-frequency especially kHz-band signals, which hold pivotal value in applications such as long-range navigation, ground-penetrating radar, and underwater communication. However, the capability of kHz atomic receivers remains severely constrained by the shielding effects of adsorbed alkali metal atoms. Here, we propose a conceptually new self-dressing kHz signal measurement paradigm by converting the undesired coupling-laser-induced DC field to an atomic dressing, and deftly building atomic superheterodyne inside the sapphire vapor cell, which is prepared to adequately suppress the low-frequency shielding through resistivity manipulation engineering. Further, we realize strengthened interaction between the atoms and kHz field by localized enhancement of the incident signals, and finally achieve an ultrahigh sensitivity of 13.5 nV/cm/Hz1/2 at 100 kHz. This architecture represents a significant advance, with the potential to greatly accelerate the practical applications of Rydberg atomic receivers in kHz-band detection, communication, and related fields.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"32 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146152298","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}
Pub Date : 2026-02-06DOI: 10.1038/s41535-026-00853-z
Markus Weißenhofer, M. S. Mrudul, Sergiy Mankovsky, Peter M. Oppeneer
Rotating magnon wave packets carrying orbital moments offer a pathway to unconventional transport phenomena. Here, we investigate magnon orbital moments and the magnon orbital Nernst effect in the prototypical altermagnets RuO 2 and CrSb using first-principles calculations, linear response theory, and symmetry analysis. While symmetry constraints enforce vanishing equilibrium magnon orbital moments, we find that in thermal non-equilibrium a finite and robust magnon orbital Nernst effect emerges from the anisotropic Heisenberg exchange, regardless of spin-orbit coupling. This effect is intrinsically tied to the unique exchange splitting of magnon dispersions in altermagnets and is absent in conventional antiferromagnets. Magnon orbital moment transport displays markedly reduced sensitivity to the orientation of the Néel vector, temperature gradient, and magnetic domain structure compared to the magnon spin Seebeck and spin Nernst effects, enabling its persistence even in polycrystalline samples with arbitrary domain configurations. Our results position magnon orbital transport as a promising and robust functional mechanism for orbitronic and spintronic devices, and as a potential indirect probe of altermagnetism in disordered insulating systems.
{"title":"Magnon orbital Nernst effect in altermagnets","authors":"Markus Weißenhofer, M. S. Mrudul, Sergiy Mankovsky, Peter M. Oppeneer","doi":"10.1038/s41535-026-00853-z","DOIUrl":"https://doi.org/10.1038/s41535-026-00853-z","url":null,"abstract":"Rotating magnon wave packets carrying orbital moments offer a pathway to unconventional transport phenomena. Here, we investigate magnon orbital moments and the magnon orbital Nernst effect in the prototypical altermagnets RuO <jats:sub>2</jats:sub> and CrSb using first-principles calculations, linear response theory, and symmetry analysis. While symmetry constraints enforce vanishing equilibrium magnon orbital moments, we find that in thermal non-equilibrium a finite and robust magnon orbital Nernst effect emerges from the anisotropic Heisenberg exchange, regardless of spin-orbit coupling. This effect is intrinsically tied to the unique exchange splitting of magnon dispersions in altermagnets and is absent in conventional antiferromagnets. Magnon orbital moment transport displays markedly reduced sensitivity to the orientation of the Néel vector, temperature gradient, and magnetic domain structure compared to the magnon spin Seebeck and spin Nernst effects, enabling its persistence even in polycrystalline samples with arbitrary domain configurations. Our results position magnon orbital transport as a promising and robust functional mechanism for orbitronic and spintronic devices, and as a potential indirect probe of altermagnetism in disordered insulating systems.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"16 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135495","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}
Pub Date : 2026-02-06DOI: 10.1038/s41535-026-00860-0
N. Drichko, V. S. Thoi, N. P. Armitage
{"title":"Much ado about MOFs: metal-organic-frameworks as quantum materials","authors":"N. Drichko, V. S. Thoi, N. P. Armitage","doi":"10.1038/s41535-026-00860-0","DOIUrl":"https://doi.org/10.1038/s41535-026-00860-0","url":null,"abstract":"","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"30 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135497","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}
We report the electronic structure of the thermoelectric semimetal Ta 2 PdSe 6 with a large thermoelectric power factor and giant Peltier conductivity by means of angle-resolved photoemission spectroscopy (ARPES). The ARPES spectra reveal the coexistence of a sharp hole band with a light electron mass and a broad electron band with a relatively heavy electron mass, which originate from different quasi-one-dimensional (Q1D) chains in Ta 2 PdSe 6 . Moreover, the electron band around the Brillouin-zone (BZ) boundary shows a replica structure with respect to the energy originating from plasmonic polarons due to electron-plasmon interactions. The different scattering effects and interactions in each atomic chain lead to asymmetric transport lifetimes of carriers: a large Seebeck coefficient can be realized even in a semimetal. Our findings pave the way for exploring the thermoelectric materials in previously overlooked semimetals and provide a new platform for low-temperature thermoelectric physics, which has been challenging with semiconductors.
{"title":"Band-selective plasmonic polaron in thermoelectric semimetal Ta2PdSe6 with ultra-high power factor","authors":"Daiki Ootsuki, Akitoshi Nakano, Urara Maruoka, Takumi Hasegawa, Masashi Arita, Miho Kitamura, Koji Horiba, Teppei Yoshida, Ichiro Terasaki","doi":"10.1038/s41535-026-00858-8","DOIUrl":"https://doi.org/10.1038/s41535-026-00858-8","url":null,"abstract":"We report the electronic structure of the thermoelectric semimetal Ta <jats:sub>2</jats:sub> PdSe <jats:sub>6</jats:sub> with a large thermoelectric power factor and giant Peltier conductivity by means of angle-resolved photoemission spectroscopy (ARPES). The ARPES spectra reveal the coexistence of a sharp hole band with a light electron mass and a broad electron band with a relatively heavy electron mass, which originate from different quasi-one-dimensional (Q1D) chains in Ta <jats:sub>2</jats:sub> PdSe <jats:sub>6</jats:sub> . Moreover, the electron band around the Brillouin-zone (BZ) boundary shows a replica structure with respect to the energy originating from plasmonic polarons due to electron-plasmon interactions. The different scattering effects and interactions in each atomic chain lead to asymmetric transport lifetimes of carriers: a large Seebeck coefficient can be realized even in a semimetal. Our findings pave the way for exploring the thermoelectric materials in previously overlooked semimetals and provide a new platform for low-temperature thermoelectric physics, which has been challenging with semiconductors.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"7 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146135496","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}
Pub Date : 2026-02-04DOI: 10.1038/s41535-026-00859-7
Marvin Kopp, Charu Garg, Sarah Krebber, Kristin Kliemt, Cornelius Krellner, Sudhaman R. Balguri, Mira Mahendru, Fazel Tafti, Theodore L. Breeze, Nathan P. Bentley, Francis L. Pratt, Thomas J. Hicken, Hubertus Luetkens, Jonas A. Krieger, Stephen J. Blundell, Tom Lancaster, M. Victoria Ale Crivillero, Steffen Wirth, Jens Müller
The interplay between magnetism and charge transport is central to understanding colossal magnetoresistance (CMR), a phenomenon well studied in ferromagnets. Recently, antiferromagnetic (AFM) EuCd 2 P 2 has attracted considerable interest due to its remarkable CMR, for which magnetic fluctuations and the formation of ferromagnetic clusters have been proposed as key mechanisms. Here we provide direct evidence that these effects originate from the formation and percolation of magnetic polarons. We employ a complementary set of sensitive probes that allows for a direct comparison of electronic and magnetic properties on multiple time scales revealing pronounced electronic and magnetic phase separation below T* ≈ 2 TN . These measurements indicate an inhomogeneous, percolating electronic system below T* and well above the magnetic ordering temperature TN = 11 K. In applied magnetic fields, the onset of the pronounced negative MR in the paramagnetic regime emerges at a universal critical magnetization. The characteristic size of the magnetic polarons near the percolation threshold is estimated to be ~6−10 nm. Our results establish dynamic polaron percolation within an AFM matrix as the microscopic origin of CMR in EuCd 2 P 2 , providing a unified framework for magnetotransport in Eu-based correlated semiconductors.
{"title":"Robust magnetic polaron percolation in the antiferromagnetic CMR system EuCd2P2","authors":"Marvin Kopp, Charu Garg, Sarah Krebber, Kristin Kliemt, Cornelius Krellner, Sudhaman R. Balguri, Mira Mahendru, Fazel Tafti, Theodore L. Breeze, Nathan P. Bentley, Francis L. Pratt, Thomas J. Hicken, Hubertus Luetkens, Jonas A. Krieger, Stephen J. Blundell, Tom Lancaster, M. Victoria Ale Crivillero, Steffen Wirth, Jens Müller","doi":"10.1038/s41535-026-00859-7","DOIUrl":"https://doi.org/10.1038/s41535-026-00859-7","url":null,"abstract":"The interplay between magnetism and charge transport is central to understanding colossal magnetoresistance (CMR), a phenomenon well studied in ferromagnets. Recently, antiferromagnetic (AFM) EuCd <jats:sub>2</jats:sub> P <jats:sub>2</jats:sub> has attracted considerable interest due to its remarkable CMR, for which magnetic fluctuations and the formation of ferromagnetic clusters have been proposed as key mechanisms. Here we provide direct evidence that these effects originate from the formation and percolation of magnetic polarons. We employ a complementary set of sensitive probes that allows for a direct comparison of electronic and magnetic properties on multiple time scales revealing pronounced electronic and magnetic phase separation below <jats:italic>T</jats:italic> <jats:sup>*</jats:sup> ≈ 2 <jats:italic>T</jats:italic> <jats:sub> <jats:italic>N</jats:italic> </jats:sub> . These measurements indicate an inhomogeneous, percolating electronic system below <jats:italic>T</jats:italic> <jats:sup>*</jats:sup> and well above the magnetic ordering temperature <jats:italic>T</jats:italic> <jats:sub> <jats:italic>N</jats:italic> </jats:sub> = 11 K. In applied magnetic fields, the onset of the pronounced negative MR in the paramagnetic regime emerges at a universal critical magnetization. The characteristic size of the magnetic polarons near the percolation threshold is estimated to be ~6−10 nm. Our results establish dynamic polaron percolation within an AFM matrix as the microscopic origin of CMR in EuCd <jats:sub>2</jats:sub> P <jats:sub>2</jats:sub> , providing a unified framework for magnetotransport in Eu-based correlated semiconductors.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"22 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115719","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}
Pub Date : 2026-01-31DOI: 10.1038/s41535-026-00851-1
Chaebin Kim, Olivia Vilella, Youjin Lee, Pyeongjae Park, Yeochan An, Woonghee Cho, Matthew B. Stone, Alexander I. Kolesnikov, Yiqing Hao, Shinichiro Asai, Shinichi Itoh, Takatsugu Masuda, Sakib Matin, Yuna Kim, Sung-Jin Kim, Martin Mourigal, Je-Geun Park
Topological spin textures are a spectacular manifestation of the chirality of the magnetic nanostructures protected by topology. Most known skyrmion systems are restricted to a topological charge of one, require an external magnetic field for stabilization, and are only reported in a few materials. Here, we investigate the possibility that the Kitaev anisotropic-exchange interaction stabilizes a higher-order skyrmion crystal in the insulating van der Waals magnet NiI2. We unveil and explain the incommensurate static and dynamic magnetic correlations across three temperature-driven magnetic phases of this compound using neutron scattering measurements, simulations, and modeling. Our parameter optimisation yields a minimal Kitaev-Heisenberg Hamiltonian for NiI2 which reproduces the experimentally observed magnetic excitations. Monte Carlo simulations for this model predict the emergence of the higher-order skyrmion crystal but neutron diffraction and optical experiments in the candidate intermediate temperature regime are inconclusive. We discuss possible deviations from the Kitaev-Heisenberg model that explains our results and conclude that NiI2, in addition to multiferroic properties in the bulk and few-layer limits, is a Kitaev bulk material proximate to the finite temperature higher-order skyrmion crystal phase.
{"title":"Kitaev interaction and proximate higher-order skyrmion crystal in the triangular lattice van der Waals antiferromagnet NiI2","authors":"Chaebin Kim, Olivia Vilella, Youjin Lee, Pyeongjae Park, Yeochan An, Woonghee Cho, Matthew B. Stone, Alexander I. Kolesnikov, Yiqing Hao, Shinichiro Asai, Shinichi Itoh, Takatsugu Masuda, Sakib Matin, Yuna Kim, Sung-Jin Kim, Martin Mourigal, Je-Geun Park","doi":"10.1038/s41535-026-00851-1","DOIUrl":"https://doi.org/10.1038/s41535-026-00851-1","url":null,"abstract":"Topological spin textures are a spectacular manifestation of the chirality of the magnetic nanostructures protected by topology. Most known skyrmion systems are restricted to a topological charge of one, require an external magnetic field for stabilization, and are only reported in a few materials. Here, we investigate the possibility that the Kitaev anisotropic-exchange interaction stabilizes a higher-order skyrmion crystal in the insulating van der Waals magnet NiI2. We unveil and explain the incommensurate static and dynamic magnetic correlations across three temperature-driven magnetic phases of this compound using neutron scattering measurements, simulations, and modeling. Our parameter optimisation yields a minimal Kitaev-Heisenberg Hamiltonian for NiI2 which reproduces the experimentally observed magnetic excitations. Monte Carlo simulations for this model predict the emergence of the higher-order skyrmion crystal but neutron diffraction and optical experiments in the candidate intermediate temperature regime are inconclusive. We discuss possible deviations from the Kitaev-Heisenberg model that explains our results and conclude that NiI2, in addition to multiferroic properties in the bulk and few-layer limits, is a Kitaev bulk material proximate to the finite temperature higher-order skyrmion crystal phase.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"8 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146089891","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}
Pub Date : 2026-01-22DOI: 10.1038/s41535-026-00849-9
Thomas A. Maier, Peter Doak, Ling-Fang Lin, Yang Zhang, Adriana Moreo, Elbio Dagotto
The discovery of <jats:italic>T</jats:italic> <jats:sub> <jats:italic>c</jats:italic> </jats:sub> ~ 80 K superconductivity in pressurized La <jats:sub>3</jats:sub> Ni <jats:sub>2</jats:sub> O <jats:sub>7</jats:sub> has launched a new platform to study high-temperature superconductivity. Using non-perturbative dynamic cluster approximation quantum Monte Carlo calculations, we characterize the magnetic and superconducting pairing behavior of a realistic bilayer two-orbital Hubbard-Hund model of this system that describes the relevant Ni <jats:italic>e</jats:italic> <jats:sub> <jats:italic>g</jats:italic> </jats:sub> states with physically relevant interaction strengths. We find a leading <jats:italic>s</jats:italic> <jats:sup>±</jats:sup> superconducting instability in this model at a temperature <jats:italic>T</jats:italic> ~ 100 K close to the experimentally observed <jats:italic>T</jats:italic> <jats:sub> <jats:italic>c</jats:italic> </jats:sub> . Analyzing the orbital and spatial structure of the effective pairing interaction giving rise to this state reveals that the interaction predominantly acts between local interlayer pairs of the <jats:inline-formula> <jats:alternatives> <jats:tex-math>$${d}_{3{z}^{2}-{r}^{2}}$$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>d</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> <mml:msup> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>-</mml:mo> <mml:msup> <mml:mrow> <mml:mi>r</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:msub> </mml:math> </jats:alternatives> </jats:inline-formula> orbital. By correlating the strength of the interaction with that of the magnetic spin fluctuations we show that it is driven by strong interlayer spin-fluctuations arising from the <jats:inline-formula> <jats:alternatives> <jats:tex-math>$${d}_{3{z}^{2}-{r}^{2}}$$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>d</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> <mml:msup> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>-</mml:mo> <mml:msup> <mml:mrow> <mml:mi>r</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:msub> </mml:math> </jats:alternatives> </jats:inline-formula> orbital. These results provide first-time non-perturbative evidence supporting the picture that a simple single-orbital bilayer Hubbard model for the Ni <jats:inline-formula> <jats:alternatives> <jats:tex-math>$${d}_{3{z}^{2}-{r}^{2}}$$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>d</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> <mml:msup> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>-</mml:mo> <mml:msup> <mml:mrow> <mml:mi>r</m
{"title":"Interlayer pairing in bilayer nickelates","authors":"Thomas A. Maier, Peter Doak, Ling-Fang Lin, Yang Zhang, Adriana Moreo, Elbio Dagotto","doi":"10.1038/s41535-026-00849-9","DOIUrl":"https://doi.org/10.1038/s41535-026-00849-9","url":null,"abstract":"The discovery of <jats:italic>T</jats:italic> <jats:sub> <jats:italic>c</jats:italic> </jats:sub> ~ 80 K superconductivity in pressurized La <jats:sub>3</jats:sub> Ni <jats:sub>2</jats:sub> O <jats:sub>7</jats:sub> has launched a new platform to study high-temperature superconductivity. Using non-perturbative dynamic cluster approximation quantum Monte Carlo calculations, we characterize the magnetic and superconducting pairing behavior of a realistic bilayer two-orbital Hubbard-Hund model of this system that describes the relevant Ni <jats:italic>e</jats:italic> <jats:sub> <jats:italic>g</jats:italic> </jats:sub> states with physically relevant interaction strengths. We find a leading <jats:italic>s</jats:italic> <jats:sup>±</jats:sup> superconducting instability in this model at a temperature <jats:italic>T</jats:italic> ~ 100 K close to the experimentally observed <jats:italic>T</jats:italic> <jats:sub> <jats:italic>c</jats:italic> </jats:sub> . Analyzing the orbital and spatial structure of the effective pairing interaction giving rise to this state reveals that the interaction predominantly acts between local interlayer pairs of the <jats:inline-formula> <jats:alternatives> <jats:tex-math>$${d}_{3{z}^{2}-{r}^{2}}$$</jats:tex-math> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mrow> <mml:mi>d</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> <mml:msup> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>-</mml:mo> <mml:msup> <mml:mrow> <mml:mi>r</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:msub> </mml:math> </jats:alternatives> </jats:inline-formula> orbital. By correlating the strength of the interaction with that of the magnetic spin fluctuations we show that it is driven by strong interlayer spin-fluctuations arising from the <jats:inline-formula> <jats:alternatives> <jats:tex-math>$${d}_{3{z}^{2}-{r}^{2}}$$</jats:tex-math> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mrow> <mml:mi>d</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> <mml:msup> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>-</mml:mo> <mml:msup> <mml:mrow> <mml:mi>r</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:msub> </mml:math> </jats:alternatives> </jats:inline-formula> orbital. These results provide first-time non-perturbative evidence supporting the picture that a simple single-orbital bilayer Hubbard model for the Ni <jats:inline-formula> <jats:alternatives> <jats:tex-math>$${d}_{3{z}^{2}-{r}^{2}}$$</jats:tex-math> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mrow> <mml:mi>d</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> <mml:msup> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>-</mml:mo> <mml:msup> <mml:mrow> <mml:mi>r</m","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"101 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033153","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}
Pub Date : 2026-01-20DOI: 10.1038/s41535-026-00852-0
Tristan R. Cao, Hengdi Zhao, Xudong Huai, Arabella Quane, Thao T. Tran, Feng Ye, Gang Cao
We demonstrate that applying modest magnetic fields (<0.1 T) during high-temperature crystal growth can profoundly alter the structure and ground state of a spin-orbit-coupled, antiferromagnetic trimer lattice. Using BaIrO₃ as a model system, whose ground state is intricately dictated by the trimer lattice, we show that magneto-synthesis, a field-assisted synthesis approach, stabilizes a structurally compressed, metastable metallic and magnetically suppressed phases inaccessible via conventional methods. These effects include a 0.85% reduction in unit cell, 4-order-of-magnitude decrease in resistivity, a 10-fold enhancement of the Sommerfeld coefficient, and the collapse of long-range magnetic order -- all intrinsic and bulk in origin. First-principles calculations confirm that the field-stabilized structure lies substantially above the ground state in energy, highlighting its metastable character. These large, coherent and correlated changes across multiple bulk properties, unlike those caused by dilute impurities, defects or off-stoichiometry, point to an intrinsic field-induced mechanism. The findings establish magneto-synthesis as a powerful new pathway for accessing non-equilibrium quantum phases in strongly correlated materials.
{"title":"Field-tailoring quantum materials via magneto-synthesis: metastable metallic and magnetically suppressed phases in a trimer iridate","authors":"Tristan R. Cao, Hengdi Zhao, Xudong Huai, Arabella Quane, Thao T. Tran, Feng Ye, Gang Cao","doi":"10.1038/s41535-026-00852-0","DOIUrl":"https://doi.org/10.1038/s41535-026-00852-0","url":null,"abstract":"We demonstrate that applying modest magnetic fields (<0.1 T) during high-temperature crystal growth can profoundly alter the structure and ground state of a spin-orbit-coupled, antiferromagnetic trimer lattice. Using BaIrO₃ as a model system, whose ground state is intricately dictated by the trimer lattice, we show that magneto-synthesis, a field-assisted synthesis approach, stabilizes a structurally compressed, metastable metallic and magnetically suppressed phases inaccessible via conventional methods. These effects include a 0.85% reduction in unit cell, 4-order-of-magnitude decrease in resistivity, a 10-fold enhancement of the Sommerfeld coefficient, and the collapse of long-range magnetic order -- all intrinsic and bulk in origin. First-principles calculations confirm that the field-stabilized structure lies substantially above the ground state in energy, highlighting its metastable character. These large, coherent and correlated changes across multiple bulk properties, unlike those caused by dilute impurities, defects or off-stoichiometry, point to an intrinsic field-induced mechanism. The findings establish magneto-synthesis as a powerful new pathway for accessing non-equilibrium quantum phases in strongly correlated materials.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"45 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146006028","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}
Pub Date : 2026-01-19DOI: 10.1038/s41535-025-00831-x
Wenfeng Wu, Eric Jacob, Viktor Christiansson, Ying Gao, Zhi Zeng, Karsten Held, Liang Si
Recent experimental discoveries of infinite- and finite-layer nickelate superconductors have highlighted the importance of a single-band {d}_{{x}^{2}-{y}^{2}}{d}_{{x}^{2}-{y}^{2}} Fermi surface for enabling unconventional superconductivity similar to cuprates. Motivated by this, we use density functional theory (DFT) and dynamical mean-field theory (DMFT) to identify two infinite-layer fluorides—KNiF2 and KPdF2—as promising candidates. Both materials exhibit strong correlations, structural stability, a single-band {d}_{{x}^{2}-{y}^{2}}{d}_{{x}^{2}-{y}^{2}} Fermi surface, and an antiferromagnetic Mott insulating state for the undoped parent compound. However, in KNiF2, overly strong correlations suppress spin fluctuations, preventing the electron pairing and superconducting states at finite temperatures. In contrast, KPdF2 offers tunable superconducting behavior. Using dynamical vertex approximation (DΓA), we show that 20% hole doping on SrTiO3 and 10% electron doping on MgO substrate yield superconducting transition temperatures of 65 K and 63 K, respectively, demonstrating the material’s potential through doping and substrate engineering.
{"title":"Single-band fluorides akin to infinite-layer cuprate superconductors","authors":"Wenfeng Wu, Eric Jacob, Viktor Christiansson, Ying Gao, Zhi Zeng, Karsten Held, Liang Si","doi":"10.1038/s41535-025-00831-x","DOIUrl":"https://doi.org/10.1038/s41535-025-00831-x","url":null,"abstract":"Recent experimental discoveries of infinite- and finite-layer nickelate superconductors have highlighted the importance of a single-band {d}_{{x}^{2}-{y}^{2}}{d}_{{x}^{2}-{y}^{2}} Fermi surface for enabling unconventional superconductivity similar to cuprates. Motivated by this, we use density functional theory (DFT) and dynamical mean-field theory (DMFT) to identify two infinite-layer fluorides—KNiF2 and KPdF2—as promising candidates. Both materials exhibit strong correlations, structural stability, a single-band {d}_{{x}^{2}-{y}^{2}}{d}_{{x}^{2}-{y}^{2}} Fermi surface, and an antiferromagnetic Mott insulating state for the undoped parent compound. However, in KNiF2, overly strong correlations suppress spin fluctuations, preventing the electron pairing and superconducting states at finite temperatures. In contrast, KPdF2 offers tunable superconducting behavior. Using dynamical vertex approximation (DΓA), we show that 20% hole doping on SrTiO3 and 10% electron doping on MgO substrate yield superconducting transition temperatures of 65 K and 63 K, respectively, demonstrating the material’s potential through doping and substrate engineering.","PeriodicalId":19283,"journal":{"name":"npj Quantum Materials","volume":"31 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146006030","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}
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