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

Negative compressibility is a sign of thermodynamic instability of open1, 2, 3 or non-equilibrium4, 5 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 systems6, 7, 8, 9, 10, 11. 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.
Authors:
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Publication Date:
OSTI Identifier:
1335078
Report Number(s):
SLAC-PUB--16757
Journal ID: ISSN 1476-1122; arXiv:1409.8253
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nature Materials; Journal Volume: 14; Journal Issue: 6
Publisher:
Nature Publishing Group
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE Electronic devices; Electronic properties and materials; Metamaterials; Superconducting properties and materials