Chromium at High Pressures: Weak Coupling and Strong Fluctuations in an Itinerant Antiferromagnet

Abstract

The spin- and charge-density-wave order parameters of the itinerant antiferromagnet chromium are measured directly with non-resonant x-ray diffraction as the system is driven towards its quantum critical point with high pressure using a diamond anvil cell. The exponential decrease of the spin and charge diffraction intensities with pressure confirms the harmonic scaling of spin and charge, while the evolution of the incommensurate ordering vector provides important insight into the difference between pressure and chemical doping as means of driving quantum phase transitions. Measurement of the charge density wave over more than two orders of magnitude of diffraction intensity provides the clearest demonstration to date of a weakly-coupled, BCS-like ground state. Evidence for the coexistence of this weakly-coupled ground state with high-energy excitations and pseudogap formation above the ordering temperature in chromium, the charge-ordered perovskite manganites, and the blue bronzes, among other such systems, raises fundamental questions about the distinctions between weak and strong coupling.

11 pages, 9 figures (8 in color)

References in corpus (13)

• Quantum criticality
• Coexisting charge modulation and ferromagnetism produces long period phases in manganites: new example of electronic soft matter
• Nodal quasiparticle in pseudogapped colossal magnetoresistive manganites
• Sliding charge density wave in manganites
• Weak charge-lattice coupling requires reinterpretation of stripes of charge order in La1-xCaxMnO3
• High Resolution Study of Magnetic Ordering at Absolute Zero
• Quantum criticality around metal-insulator transitions of strongly correlated electrons
• The strongly enhanced magnetic excitations near the quantum critical point of Cr${}_{1-x}$V${}_x$ and why strong exchange enhancement need not imply heavy fermion behavior
• Charge Ordering Fluctuation and Optical Pseudogap in La${}_{1-x}$Ca${}_x$MnO${}_3$
• Pressure-Tuned Spin and Charge Ordering in an Itinerant Antiferromagnet
• Strain control of superlattice implies weak charge-lattice coupling in La${}_{0.5}$Ca${}_{0.5}$MnO${}_3$
• Mott-Hubbard quantum criticality in paramagnetic CMR pyrochlores
• Pseudogaps in Nested Antiferromagnets

Cited by in corpus (9)

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• Quantum criticality with a twist - interplay of correlations and Kohn anomalies in three dimensions
• Evidence for Coexistence of Superconductivity and Magnetism in Single Crystals of Co-doped SrFe${}_2$As${}_2$
• Magnons in antiferromagnetic bcc-Cr and Cr${}_2$O${}_3$ from time-dependent density functional theory
• Itinerant magnetism of chromium under pressure: a DFT+DMFT study
• Neutron, electron and X-ray scattering investigation of Cr1-xVx near Quantum Criticality
• Pressure-induced Spin-Peierls to Incommensurate Charge-Density-Wave Transition in the Ground State of TiOCl