Electronic and structural ground state of heavy alkali metals at high pressure

Abstract

Alkali metals display unexpected properties at high pressure, including emergence of low symmetry crystal structures, that appear to occur due to enhanced electronic correlations among the otherwise nearly-free conduction electrons. We investigate the high pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with ab initio theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the oC84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of the valence electrons characterized by pseudo-gap formation near the Fermi level and strong spd hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.

arXiv comment10 pages, 8 figures

References in corpus (14)

• Transparent dense sodium
• Nature of the 5f states in actinide metals
• Superconducting phase diagram of Li Metal in nearly hydrostatic pressures up to 67 GPa
• Superconductivity in lithium, potassium and aluminium under extreme pressure: A first-principles study
• On the constitution of sodium at higher densities
• Volume-Collapse Transitions in the Rare Earth Metals
• Probing the gamma-alpha Transition in Bulk Ce under Pressure: A Direct Investigation by Resonant Inelastic X-ray Scattering
• Interstitial Electronic Localization
• Pressure-induced s-band ferromagnetism in alkali metals
• Origin of complex crystal structures of elements at pressure
• Theoretical Predictions of Superconductivity in Alkali Metals under High Pressure
• Different routes to pressure-induced volume collapse transitions in gadolinium and terbium metals
• Structure stability in the simple element sodium under pressure
• Plasmons in Sodium under Pressure: Increasing Departure from Nearly-Free-Electron Behavior

Cited by in corpus (3)

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• Evidence for superconductivity in Rb metal above 55 GPa pressure