scholarly journals Direct visualization of coexisting channels of interaction in CeSb

2019 ◽  
Vol 5 (3) ◽  
pp. eaat7158 ◽  
Author(s):  
Sooyoung Jang ◽  
Robert Kealhofer ◽  
Caolan John ◽  
Spencer Doyle ◽  
Ji-Sook Hong ◽  
...  
Keyword(s):  
Heavy Fermion ◽  
Real Space ◽  
Photoemission Spectroscopy ◽  
Itinerant Electron ◽  
Electron Systems ◽  
Direct Visualization ◽  
Correlated Electron Systems ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Correlated Electron ◽  
Modes Of Interaction

Our understanding of correlated electron systems is vexed by the complexity of their interactions. Heavy fermion compounds are archetypal examples of this physics, leading to exotic properties that weave magnetism, superconductivity and strange metal behavior together. The Kondo semimetal CeSb is an unusual example where different channels of interaction not only coexist, but have coincident physical signatures, leading to decades of debate about the microscopic picture describing the interactions between the f moments and the itinerant electron sea. Using angle-resolved photoemission spectroscopy, we resonantly enhance the response of the Ce f electrons across the magnetic transitions of CeSb and find there are two distinct modes of interaction that are simultaneously active, but on different kinds of carriers. This study reveals how correlated systems can reconcile the coexistence of different modes on interaction—by separating their action in momentum space, they allow their coexistence in real space.

HEAVY FERMIONS — THEIR MAGNETISM AND SUPERCONDUCTIVITY

1993 ◽  
Vol 07 (01n03) ◽  
pp. 2-8 ◽  
Author(s):  
F. STEGLICH ◽  
C. GEIBEL ◽  
A. LOIDL ◽  
G. SPARN ◽  
C. D. BREDL ◽  
...  
Keyword(s):  
Long Range ◽  
Heavy Fermion ◽  
Local Moment ◽  
Antiferromagnetic Order ◽  
Electron Systems ◽  
Correlated Electron Systems ◽  
Cooperative Phenomena ◽  
Correlated Electron ◽  
Highly Correlated ◽  
Heavy Fermion Superconductivity

Heavy-fermion compounds are ideally suited to study cooperative phenomena in highly correlated electron systems. We discuss local-moment magnetism and heavy-fermion band magnetism in the exemplary systems CeCu 2 Ge 2 and Ni-rich Ce(Cu 1− x Ni x )2 Ge 2, respectively. In addition, the coexistence of long-range antiferromagnetic order and heavy-fermion superconductivity in UM 2 Al 3 (M: Ni, Pd) will be addressed.

PROGRESS OF HIGH-RESOLUTION PHOTOEMISSION SPECTROSCOPY IN STRONGLY CORRELATED ELECTRON SYSTEMS

2002 ◽  
Vol 09 (02) ◽  
pp. 995-1006 ◽  
Author(s):  
TAKASHI TAKAHASHI
Keyword(s):  
High Resolution ◽  
High Temperature Superconductors ◽  
Current Status ◽  
Photoemission Spectroscopy ◽  
Strongly Correlated Electron Systems ◽  
Strongly Correlated ◽  
Electron Systems ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Correlated Electron

Recent progress in the energy and momentum resolutions in photoemission spectroscopy (PES) is remarkable, enabling a new challenge to long-standing and/or current fundamental problems in the strongly correlated electron systems. We review the history, current status, and future of high-resolution PES by showing representative experimental results on high-temperature superconductors, low-dimensional materials and heavy fermion f electron compounds.

RECENT DEVELOPMENT IN SOFT X-RAY SPECTROSCOPY OF CORRELATED MATERIALS: HIGH RESOLUTION ABSORPTION AND BULK-SENSITIVE PHOTOEMISSION

2002 ◽  
Vol 09 (02) ◽  
pp. 1221-1228 ◽  
Author(s):  
SHIGEMASA SUGA
Keyword(s):  
Photoelectron Spectroscopy ◽  
Light Sources ◽  
Electron Systems ◽  
Correlated Electron Systems ◽  
X Ray ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Correlated Electron ◽  
Line Spacing ◽  
Fundamental Radiation ◽  
Grating Monochromator

An extremely high quality soft X-ray beam line was constructed at BL25SU of SPring-8. A varied line spacing plane grating monochromator (VLSPGM) equipped with gratings with the central groove density of 600 and 1,000/mm can cover the energy region from 0.22 to 2 keV by the use of the fundamental radiation from the twin helical undulator. The energy resolution of VLSPGM is beyond 20,000 at 1 keV. The total resolution of practical photoelectron spectroscopy (PES) of better than 80 meV is achieved at 880 eV. The PES measurements performed above several hundred eV have shown the bulk sensitivity in many materials and provided spectra much different from the surface-sensitive spectra so far obtained below slightly above 100 eV or by He II and I light sources. As a breakthrough, bulk-sensitive angle-resolved photoemission spectroscopy (ARPES) is demonstrated to be a very powerful means of studying the bulk electronic states of correlated electron systems.

Uranium (and Cerium) Compounds At High Pressures and Magnetic Fields

2003 ◽  
Vol 802 ◽  
Author(s):  
Andrew L. Cornelius ◽  
Ravhi S. Kumar ◽  
Brian E. Light
Keyword(s):  
Magnetic Fields ◽  
Heavy Fermion ◽  
High Pressures ◽  
Direct Result ◽  
Strong Interactions ◽  
High Magnetic Fields ◽  
Electron Systems ◽  
Correlated Electron Systems ◽  
Range Magnetic Order ◽  
Correlated Electron

ABSTRACTCorrelated-electron systems are so named due to strong interactions between electrons unlike traditional metals (e.g. copper) that have “free electrons” that interact very weakly. Knowledge of the Fermi surface, density of electron states and band structure are the starting points for a first-principles understanding of the electronic and electronically related macroscopic properties, e.g. equation of state. The use of high pressure and high magnetic fields to alter the electron-electron (hybridization) and electron-lattice interactions give us powerful tools to understand complicated rare earth and actinide correlated-electron systems and allows precise testing of experiment to theory. Correlated-electron systems yield a wide variety of ground states that are a direct result of the hybridization strength including: short and long range magnetic order, spin fluctuating, enhanced Pauli paramagnetism, heavy fermion behavior and superconductivity. We will review some results on U compounds in high magnetic fields and high pressures. By comparing the results to Ce compounds that have significantly more localized f electrons, the effect of direct 5f electron wavefunction overlap in U compounds can be discerned. Consequences on the search for U based heavy fermion superconductors will be discussed.

scholarly journals Itinerant ferromagnetism of the Pd-terminated polar surface of PdCoO2

2018 ◽  
Vol 115 (51) ◽  
pp. 12956-12960 ◽  
Author(s):  
Federico Mazzola ◽  
Veronika Sunko ◽  
Seunghyun Khim ◽  
Helge Rosner ◽  
Pallavi Kushwaha ◽  
...  
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Antiferromagnetic Order ◽  
Electron Systems ◽  
Surface Polarity ◽  
Itinerant Ferromagnetism ◽  
Correlated Electron Systems ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Correlated Electron ◽  
Surface Electronic Structure

The ability to modulate the collective properties of correlated electron systems at their interfaces and surfaces underpins the burgeoning field of “designer” quantum materials. Here, we show how an electronic reconstruction driven by surface polarity mediates a Stoner-like magnetic instability to itinerant ferromagnetism at the Pd-terminated surface of the nonmagnetic delafossite oxide metal PdCoO2. Combining angle-resolved photoemission spectroscopy and density-functional theory calculations, we show how this leads to a rich multiband surface electronic structure. We find similar surface state dispersions in PdCrO2, suggesting surface ferromagnetism persists in this sister compound despite its bulk antiferromagnetic order.

scholarly journals Electronic reconstruction forming a C2-symmetric Dirac semimetal in Ca3Ru2O7

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
M. Horio ◽  
Q. Wang ◽  
V. Granata ◽  
K. P. Kramer ◽  
Y. Sassa ◽  
...  
Keyword(s):  
Band Structure ◽  
Fermi Surface ◽  
Quantum Oscillation ◽  
Electron Systems ◽  
Electronic Band ◽  
Correlated Electron Systems ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Correlated Electron ◽  
Dirac Semimetal ◽  
Electronic Band Structures

AbstractElectronic band structures in solids stem from a periodic potential reflecting the structure of either the crystal lattice or electronic order. In the stoichiometric ruthenate Ca3Ru2O7, numerous Fermi surface-sensitive probes indicate a low-temperature electronic reconstruction. Yet, the causality and the reconstructed band structure remain unsolved. Here, we show by angle-resolved photoemission spectroscopy, how in Ca3Ru2O7 a C2-symmetric massive Dirac semimetal is realized through a Brillouin-zone preserving electronic reconstruction. This Dirac semimetal emerges in a two-stage transition upon cooling. The Dirac point and band velocities are consistent with constraints set by quantum oscillation, thermodynamic, and transport experiments, suggesting that the complete Fermi surface is resolved. The reconstructed structure—incompatible with translational-symmetry-breaking density waves—serves as an important test for band structure calculations of correlated electron systems.

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