Article
Materials Science, Multidisciplinary
Tommaso Gorni, Diego Florez-Ablan, Luca de'Medici
Summary: In this study, we calculate the electronic properties of the normal state of uncollapsed LaFe2As2, considering local dynamical correlations. Our results show that LaFe2As2 has a reduced bare bandwidth, which explains the substantial correlations despite its nominal valence d6.5.
Article
Materials Science, Multidisciplinary
Jianzhou Zhao, Yilin Wang, Xiaolong Feng, Shengyuan A. Yang
Summary: By comparing the electronic structures of LaFe2As2 and CaFe2As2, researchers found that they are similar in terms of electronic correlation and Fermi-surface topology, suggesting that superconductivity may also be induced in the collapsed phase of LaFe2As2 under similar conditions as for CaFe2As2.
Article
Materials Science, Multidisciplinary
Li Xiang, Mingyu Xu, Sergey L. Bud'ko, Paul C. Canfield
Summary: Resistance measurements were performed on single crystals of CaK(Fe1-xMnx)4As4 (x = 0.024) under hydrostatic pressure. The pressure dependence of the magnetic and superconducting transition temperatures, as well as the superconducting upper critical field, was investigated. The results show that the magnetic transition temperature is suppressed with increasing pressure, while the superconducting transition temperature initially increases and then decreases, reaching a maximum at a specific pressure. Furthermore, changes in the pressure dependence of the superconducting coherence length were observed at this pressure.
Article
Materials Science, Multidisciplinary
H. Pfau, M. Yi, M. Hashimoto, T. Chen, P-C Dai, Z-X Shen, S-K Mo, D. Lu
Summary: The study investigates the influence of electronic nematicity on quasiparticle coherence in detwinned FeSe using ARPES, finding an anisotropy between dxz and dyz orbitals and a more coherent dxz orbital compared to the dyz orbital. This observation contrasts with earlier predictions and underscores the importance of electronic correlations in describing nematicity.
Article
Physics, Applied
V. A. Shestakov, M. M. Korshunov, Yu N. Togushova, O. Dolgov
Summary: The study reveals that with the increase of nonmagnetic disorders, the unconventional s(+/-) state in iron-based superconductors may transform into the s(++) state, and specific signatures of this transition process exist.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Mehdi Hesani, Kourosh Rahimi, Ahmad Yazdani
Summary: The study investigated the relationship between charge doping and correlations in BaFe2As2 using DFT+DMFT, showing that electronic correlations strengthen systematically from electron-doping to hole-doping regimes. Due to its multi-orbital nature, correlations in BaFe2As2 are orbital-dependent, with the Fe-3d(xy) orbital exhibiting the most correlation.
JOURNAL OF MATERIALS SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
C. Trainer, M. Songvilay, N. Qureshi, A. Stunault, C. M. Yim, E. E. Rodriguez, C. Heil, V Tsurkan, M. A. Green, A. Loidl, P. Wahl, C. Stock
Summary: Fe1+xTe is a two-dimensional van der Waals antiferromagnet that becomes superconducting with anion substitution on the Te site. The bulk magnetic structure of Fe1+xTe shows collinear in-plane order, while the surface exhibits a magnetic surface reconstruction with a canting angle of the spins. This difference in magnetic properties between the bulk and surface of Fe1+xTe suggests that surface structural relaxation leads to an out-of-plane magnetocrystalline anisotropy.
Article
Materials Science, Multidisciplinary
Laura Fanfarillo, Angelo Valli, Massimo Capone
Summary: We demonstrate that the experimental manifestations of nematic order in iron-based superconductors are intrinsically related to electronic correlations in the Hund's correlated metallic state, and cannot be explained using a renormalized quasiparticle picture. Specifically, we find that (i) in a metal where correlations are dominated by the Hund's coupling, nematic ordering does not result in a rigid energy shift in the photoemission spectra, but rather a more complex spectral weight redistribution that reflects the experimental observations, and (ii) the nematic ordering exhibits orbital-selective coherence induced by Hund's physics, consistent with experimental observations.
Article
Physics, Condensed Matter
M. Y. Hacisalihoglu, L. Simonelli, C. Marini, A. Provino, A. Martinelli, P. Manfrinetti, M. Putti, N. L. Saini
Summary: The local structure of La(Fe1-xMnx)AsO was analyzed using temperature dependent Fe K-edge EXAFS measurements, revealing distinct behavior of Fe-As and Fe-Fe atomic displacements with temperature. The study suggests that increased iron local magnetic moment induced by Mn substitution may be the main reason for the dramatic effect observed in iron-based superconductors.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Multidisciplinary Sciences
Ye Yang, Fanghang Yu, Xikai Wen, Zhigang Gui, Yuqing Zhang, Fangyang Zhan, Rui Wang, Jianjun Ying, Xianhui Chen
Summary: Based on electrical transport and XRD measurements, as well as first-principles calculations, researchers discover a unique pressure-induced Mott transition from an antiferromagnetic Mott insulator to a ferromagnetic Weyl metal in the iron oxychalcogenide La2O3Fe2Se2 around 37 GPa without any structural change. The theoretical calculations indicate that this insulator-metal transition is mainly due to the increased bandwidth and reduced electron correlation under high pressure. Moreover, the high-pressure ferromagnetic Weyl metallic phase exhibits attractive electronic band structures with six pairs of Weyl points near the Fermi level, which can be easily manipulated by a magnetic field.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Nikita S. Pavlov, Timur K. Kim, Alexander Yaresko, Ki-Young Choi, Igor A. Nekrasov, Daniil V. Evtushinsky
Summary: The electronic spectral function of BaNi2As2 was investigated using ARPES and LDA + DMFT, showing weak correlation effects compared to iron arsenide compounds. The reduction in correlation strength in BaNi2As2 is attributed to an increase in 3d-orbital filling when transitioning from Fe to Ni.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Physics, Applied
Karciano J. S. Silva, David A. Landinez-Tellez, Petrucio Barrozo, I. Garcia-Fornaris, J. Albino Aguiar
Summary: This study reports on the sintering, structural, morphological, electrical, and magnetic characterization of the superconducting FeSe0.88. The sample was prepared using the solid-state reaction method at 600 degrees C in an evacuated borosilicate tube. X-ray diffractograms revealed the formation of two minor impurity phases, Fe7Se8 and FeSe, both with hexagonal structures, which are not superconducting. Resistivity measurements showed the onset superconducting temperature at Tconset is approximately 8.6 K. Magnetic measurements demonstrated a ferromagnetic-paramagnetic phase transition around 875 K for the FeSe0.88 compound.
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM
(2023)
Article
Physics, Multidisciplinary
Qianni Jiang, Yue Shi, Morten H. Christensen, Joshua J. Sanchez, Bevin Huang, Zhong Lin, Zhaoyu Liu, Paul Malinowski, Xiaodong Xu, Rafael M. Fernandes, Jiun-Haw Chu
Summary: In this study, the authors investigate the nematic susceptibility and its relationship with spin fluctuations in Fe1+yTe1-xSex using elastoresistivity measurement. They find that the nematic fluctuations in two symmetry channels are closely linked to the corresponding spin fluctuations, and observe an unusual temperature dependence of the nematic susceptibility attributed to the loss of coherence of the d(xy) orbital. The research highlights the importance of orbital differentiation on the nematic properties of iron-based materials.
COMMUNICATIONS PHYSICS
(2023)
Review
Chemistry, Multidisciplinary
Anna Krzton-Maziopa
Summary: Intercalated layered iron-based monochalcogenides with organic molecules show potential for fine-tuning their magnetic and electrical properties by controlling doping and organic molecule characteristics. Recent progress in intercalation chemistry has led to the discovery of new hybrid inorganic-organic phases with high superconducting transition temperatures.
FRONTIERS IN CHEMISTRY
(2021)
Review
Plant Sciences
Meijie Li, Shunsuke Watanabe, Fei Gao, Christian Dubos
Summary: Iron is an essential micronutrient for plant growth and development. Plants have evolved two different strategies, Strategy I and Strategy II, to acquire iron from soils. Recent findings show that the choice of strategy is influenced by soil characteristics, such as pH and oxygen concentration. This review summarizes recent research on plant iron uptake and discusses its impact on our understanding of plant iron nutrition.
Article
Multidisciplinary Sciences
J. A. Wilcox, M. J. Grant, L. Malone, C. Putzke, D. Kaczorowski, T. Wolf, F. Hardy, C. Meingast, J. G. Analytis, J. -H. Chu, I. R. Fisher, A. Carrington
Summary: The authors observe the existence of non-linear Meissner effect in two unconventional nodal superconductors and demonstrate its use in distinguishing nodal and non-nodal characteristics.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Jin Yue, Yilikal Ayino, Tristan K. Truttmann, Maria N. Gastiasoro, Eylon Persky, Alex Khanukov, Dooyong Lee, Laxman R. Thoutam, Beena Kalisky, Rafael M. Fernandes, Vlad S. Pribiag, Bharat Jalan
Summary: Using hybrid MBE, high-quality SrTiO₃ films with low defect density were obtained, and their transport properties were studied. The dominant influence of intraband scattering at the second Lifshitz transition was observed, along with the anomalous temperature dependence of the Hall scattering factor and carrier density due to the antiferrodistortive transition.
Article
Multidisciplinary Sciences
Pierre Massat, Jiajia Wen, Jack M. Jiang, Alexander T. Hristov, Yaohua Liu, Rebecca W. Smaha, Robert S. Feigelson, Young S. Lee, Rafael M. Fernandes, Ian R. Fisher
Summary: We report the results of measurements on TmVO4, an insulator that undergoes a continuous phase transition. Through tuning the magnetic field, we observe quantum fluctuations at high magnetic fields and find that the crystal lattice plays a crucial role in the interactions and critical behavior. Our findings have important implications for understanding quantum criticality in insulators.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Multidisciplinary Sciences
Z. Guguchia, C. Mielke, D. Das, R. Gupta, J. -X. Yin, H. Liu, Q. Yin, M. H. Christensen, Z. Tu, C. Gong, N. Shumiya, Md Shafayat Hossain, Ts Gamsakhurdashvili, M. Elender, Pengcheng Dai, A. Amato, Y. Shi, H. C. Lei, R. M. Fernandes, M. Z. Hasan, H. Luetkens, R. Khasanov
Summary: In this study, pressure-tuned and ultra-low temperature muon spin spectroscopy was used to uncover the unconventional nature of superconductivity in RbV3Sb5 and KV3Sb5. It was found that at ambient pressure, time-reversal symmetry breaking charge order was observed in RbV3Sb5, and the superconducting state displayed a nodal energy gap and reduced superfluid density. Applying pressure suppressed the charge-order transitions, increased the superfluid density, and progressively evolved the superconducting state from nodal to nodeless. The optimal superconductivity state was found to break time-reversal symmetry. These results offer unique insights into the nature of the pairing state and highlight the tunable nodal kagome superconductivity competing with time-reversal symmetry-breaking charge order.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Condensed Matter
Ruben Albertini, Salvatore Macis, Andrei A. Ivanov, Alexey P. Menushenkov, Alessandro Puri, Virginia Monteseguro, Boby Joseph, Wei Xu, Augusto Marcelli, Paula Giraldo-Gallo, Ian Randal Fisher, Antonio Bianconi, Gaetano Campi
Summary: In this study, the spatial micro-fluctuations in BaPO units in Ba(Pb-1 Bi-x(x))O-3 crystals were measured using scanning dispersive micro-X-ray absorption near edge structure technique. The results showed substantial differences between the microstrain epsilon and the chemical inhomogeneity x, and different relationships epsilon(x) were observed in samples with different doping levels.
Article
Materials Science, Multidisciplinary
Matthias Hecker, Roland Willa, Joerg Schmalian, Rafael M. Fernandes
Summary: Electronically ordered states can melt in stages, similar to liquid crystals. Superconductors with multiple components are natural candidates for vestigial order, which breaks U(1)-gauge and time-reversal or lattice symmetries. Bilinears of a generic two-component superconductor on a tetragonal or hexagonal lattice can be classified using group theory. The fluctuating regime of the superconducting Ginzburg-Landau action and the competing vestigial phases can be described using large-N and variational methods. The nematic and ferromagnetic phases are leading vestigial instabilities, while charge-4e order is an attractive but subleading vestigial channel.
Article
Materials Science, Multidisciplinary
Anzumaan R. Chakraborty, Rafael M. Fernandes
Summary: Motivated by recent observations of threefold rotational symmetry breaking in various systems, we investigate the strain-temperature phase diagram of the electronic 3-state Potts-nematic order. We find quantum critical points (QCP) when uniaxial strain is applied, leading to different types of symmetry-preserving and symmetry-breaking transitions. The existence of three minima in the nematic action also leads to interesting strain-nematic hysteresis curves.
Article
Materials Science, Multidisciplinary
Mainak Pal, Andreas Kreisel, P. J. Hirschfeld
Summary: There are proposals for platforms supporting topological superconductivity in high-temperature superconductors in order to take advantage of the larger superconducting gap and the expected robustness of Majorana zero modes. The iron-based materials offer large Tc and nodeless energy gaps, along with atomically flat surfaces that allow for engineering defect structures and measuring spectroscopic properties to reveal topological aspects. By including the correlated nature of materials and the multiband electronic structure, the authors demonstrate how correlations can lead to local magnetic order and the emergence of a topological superconducting state.
Article
Materials Science, Multidisciplinary
Mainak Pal, Andreas Kreisel, W. A. Atkinson, P. J. Hirschfeld
Summary: Theoretical studies of disordered d-wave superconductors have mainly focused on optimally doped models with strong scatterers, but it is necessary to also study the weaker scattering associated with dopant atoms in order to address recent controversies about overdoped cuprates. In this study, simple models of such systems are investigated using the self-consistent Bogoliubov-de Gennes (BdG) framework and compared to disorder-averaged results using the self-consistent T-matrix-approximation (SCTMA). The SCTMA performs well overall, except for highly disordered systems with strongly suppressed superfluid density.
Article
Materials Science, Multidisciplinary
Ipsita Mandal, Rafael M. Fernandes
Summary: The interplay between strong correlations and nontrivial topology in twisted moire systems can give rise to a rich landscape of ordered states. The properties of a system displaying long-range valley-polarized nematic order and its onset in twisted moire systems are investigated in this paper. This order breaks multiple symmetries and promotes the emergence of non-Fermi liquid behavior.
Article
Materials Science, Multidisciplinary
Avraham Klein, Vladyslav Kozii, Jonathan Ruhman, Rafael M. Fernandes
Summary: Compounds such as doped paraelectrics and polar metals can exhibit ferroelectricity along with correlated electronic phenomena. This study provides a comprehensive analysis of the properties of a metal transitioning to a ferroelectric state in both two and three dimensions. Using a minimal model, the dynamical response of electrons and phonons is computed, revealing the presence of both Fermi and non-Fermi liquid phases, enhanced pairing, and a phase diagram with various transitions. The entire phase diagram can be controlled by external strain. These findings contribute to the understanding of quantum ferroelectric metals and their potential applications.
Article
Materials Science, Multidisciplinary
Philip M. Dee, Benjamin Cohen-Stead, Steven Johnston, P. J. Hirschfeld
Summary: In a recent study, Schrodi et al. discovered an unconventional superconducting state with a sign-changing order parameter using the Migdal-Eliashberg theory. They found this unconventional solution despite using an isotropic bare electron-phonon coupling in the Hamiltonian. However, our Monte Carlo simulations on a similar model suggest that unconventional pairing correlations do not exceed their noninteracting values at any carrier concentration we have checked. Instead, strong charge-density-wave correlations persist at the lowest accessible temperatures.
Article
Materials Science, Multidisciplinary
J. A. Galvis, A. Fang, D. Jimenez-Guerrero, J. Rojas-Castillo, J. Casas, O. Herrera, A. C. Garcia-Castro, E. Bousquet, I. R. Fisher, A. Kapitulnik, P. Giraldo-Gallo
Summary: In this paper, we provide a full characterization of the charge density wave (CDW) state in NbTe4 through phonon-structure calculations and scanning tunneling microscopy measurements. Our findings reveal that the CDW in this compound is fully commensurate with the lattice parameters at short range, but discommensurate at long range with the presence of phase-slip domain walls. These results solve a long-standing discussion about the nature of the CDW in these materials and establish a strong foundation for the study of the interplay between this state and other novel quantum electronic states.
Article
Materials Science, Multidisciplinary
Steven A. Kivelson, Akshat Pandey, Anisha G. Singh, Aharon Kapitulnik, Ian R. Fisher
Summary: In this paper, we study the critical behavior of incommensurate unidirectional charge-density-wave ordering in a weakly orthorhombic system subject to uniaxial strain, which serves as an experimentally significant example of U (1) x U (1) multicriticality. Depending on microscopic details, the phase diagram can exhibit qualitatively different structures, such as vestigial metanematic critical point, a pair of tricritical points, decoupled tetracritical point, or (at least at mean-field level) bicritical point. We analyze the emergent symmetries in the critical regime and find that in some cases, an emergent Z2 order parameter symmetry can be present.
Article
Materials Science, Multidisciplinary
Virginia Gali, Rafael M. Fernandes
Summary: This study investigates the pairing instability of two-component unconventional superconductors on the triangular lattice and finds that electromagnetic field fluctuations play a crucial role in determining the superconducting state.