Spectroscopic evidence for negative electronic compressibility in a quasi-three-dimensional spin-orbit correlated metal

Abstract

Negative compressibility is a sign of thermodynamic instability of open or non-equilibrium systems. In quantum materials consisting of multiple mutually coupled subsystems, the compressibility of one subsystem can be negative if it is countered by positive compressibility of the others. Manifestations of this effect have so far been limited to low-dimensional dilute electron systems. Here we present evidence from angle-resolved photoemission spectroscopy (ARPES) for negative electronic compressibility (NEC) in the quasi-three-dimensional (3D) spin-orbit correlated metal (Sr1-xLax)3Ir2O7. Increased electron filling accompanies an anomalous decrease of the chemical potential, as indicated by the overall movement of the deep valence bands. Such anomaly, suggestive of NEC, is shown to be primarily driven by the lowering in energy of the conduction band as the correlated bandgap reduces. Our finding points to a distinct pathway towards an uncharted territory of NEC featuring bulk correlated metals with unique potential for applications in low-power nanoelectronics and novel metamaterials.

Advance online publication in Nature Materials; see the journal website for free download of Supplementary Information

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Cited by in corpus (11)

• First-order melting of a weak spin-orbit Mott insulator into a correlated metal
• Doping Evolution of Magnetic Order and Magnetic Excitations in (Sr${}_{1-x}$La${}_x$)${}_3$Ir${}_2$O${}_7$
• First-Principles Calculation of Spin and Orbital Contributions to Magnetically Ordered Moments in Sr${}_2$IrO${}_4$
• Fermi Arcs vs. Fermi Pockets in Electron-doped Perovskite Iridates
• Structural evolution and electronic properties of (Sr1-xCax)2-yIrO4+z spin-orbit assisted insulators
• Quasiparticles and charge transfer at the two surfaces of the honeycomb iridate Na${}_2$IrO${}_3$
• Hubbard-Kanamori model: spectral functions, negative electron compressibility, and susceptibilities
• Doping driven structural distortion in the bilayer iridate (Sr${}_{1-x}$La${}_x$)${}_3$Ir${}_2$O${}_7$
• Scaling Theory of a Compressibility-Driven Metal-Insulator Transition in a Two-Dimensional Electron Fluid
• Evolution of the spectral lineshape at the magnetic transition in Sr2IrO4 and Sr3Ir2O7
• Negative permittivity attests to local attractive interactions in bubble and stripe phases