Direct Observation of the Lindhard Continuum using Resonant Inelastic X-ray Scattering

Fuente: arXiv
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Autores principales: Lomeli, Eder G., Kundu, Sarbajaya, Chuang, Yi-De, Zhuo, Zengqing, Chen, Ke, Xi, Xiaoxing, Shen, Lingjia, Dakovski, Georgi L., Geprägs, Stephan, Moritz, Brian, Devereaux, Thomas P., Vinson, John, Kling, Matthias F., Huang, Edwin W., Jost, Daniel
Formato: Preprint
Publicado: 2025
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author Lomeli, Eder G.
Kundu, Sarbajaya
Chuang, Yi-De
Zhuo, Zengqing
Chen, Ke
Xi, Xiaoxing
Shen, Lingjia
Dakovski, Georgi L.
Geprägs, Stephan
Moritz, Brian
Devereaux, Thomas P.
Vinson, John
Kling, Matthias F.
Huang, Edwin W.
Jost, Daniel
author_facet Lomeli, Eder G.
Kundu, Sarbajaya
Chuang, Yi-De
Zhuo, Zengqing
Chen, Ke
Xi, Xiaoxing
Shen, Lingjia
Dakovski, Georgi L.
Geprägs, Stephan
Moritz, Brian
Devereaux, Thomas P.
Vinson, John
Kling, Matthias F.
Huang, Edwin W.
Jost, Daniel
contents Understanding the excitations of quantum materials is essential for unraveling how their microscopic constituents interact. Among these, particle-hole excitations form a particularly important class, as they govern fundamental processes such as screening, dissipation, and transport. In metals, the continuum of electron-hole excitations is described by the Lindhard function. Although central to the theory of Fermi liquids, the corresponding Lindhard continuum has remained experimentally elusive. Here, we report its direct observation in the weakly correlated metal MgB$_{2}$ using ultra-soft resonant inelastic X-ray scattering (RIXS). We resolve a linearly dispersing excitation with velocity comparable to the Fermi velocity and find quantitative agreement with simulations of the non-interacting charge susceptibility. A detailed analysis and decomposition of the simulations reveal the intra-band origin of this low-energy excitation, confirming it as the Lindhard continuum. Our results establish ultra-soft RIXS as a momentum-resolved probe of the fermiology in metals and call for deeper investigations of continuum features in RIXS and related spectroscopy of other materials beyond MgB$_{2}$.
format Preprint
id arxiv_https___arxiv_org_abs_2509_10741
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Direct Observation of the Lindhard Continuum using Resonant Inelastic X-ray Scattering
Lomeli, Eder G.
Kundu, Sarbajaya
Chuang, Yi-De
Zhuo, Zengqing
Chen, Ke
Xi, Xiaoxing
Shen, Lingjia
Dakovski, Georgi L.
Geprägs, Stephan
Moritz, Brian
Devereaux, Thomas P.
Vinson, John
Kling, Matthias F.
Huang, Edwin W.
Jost, Daniel
Strongly Correlated Electrons
Materials Science
Understanding the excitations of quantum materials is essential for unraveling how their microscopic constituents interact. Among these, particle-hole excitations form a particularly important class, as they govern fundamental processes such as screening, dissipation, and transport. In metals, the continuum of electron-hole excitations is described by the Lindhard function. Although central to the theory of Fermi liquids, the corresponding Lindhard continuum has remained experimentally elusive. Here, we report its direct observation in the weakly correlated metal MgB$_{2}$ using ultra-soft resonant inelastic X-ray scattering (RIXS). We resolve a linearly dispersing excitation with velocity comparable to the Fermi velocity and find quantitative agreement with simulations of the non-interacting charge susceptibility. A detailed analysis and decomposition of the simulations reveal the intra-band origin of this low-energy excitation, confirming it as the Lindhard continuum. Our results establish ultra-soft RIXS as a momentum-resolved probe of the fermiology in metals and call for deeper investigations of continuum features in RIXS and related spectroscopy of other materials beyond MgB$_{2}$.
title Direct Observation of the Lindhard Continuum using Resonant Inelastic X-ray Scattering
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2509.10741