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Title: Ultrafast X-Ray Absorption Spectroscopy of Strongly Correlated Systems: Core Hole Effect

Abstract

Recently, ultrafast pump-probe spectroscopy has provided insightful information about the nonequilibrium dynamics of excitations in materials. In a typical experiment of time-resolved x-ray absorption spectroscopy, the systems are excited by a femtosecond laser pulse (pump pulse) followed by an x-ray probe pulse after a time delay to measure the absorption spectra of the photoexcited systems. We present a theory for nonequilibrium x-ray absorption spectroscopy in one-dimensional strongly correlated systems. The core hole created by the x ray is modeled as an additional effective potential of the core hole site, which changes the spectrum qualitatively. In equilibrium, the spectrum reveals the charge gap at half-filling and the metal-insulator transition in the presence of the core hole effect. Moreover, a pump-probe scheme is introduced to drive the system out of equilibrium before the x-ray probe. The effects of the pump pulse with varying frequencies, shapes, and fluences are discussed for the dynamics of strongly correlated systems in and out of resonance. The spectrum suggests that the driven insulating state has a metallic droplet around the core hole. The rich structures of the nonequilibrium x-ray absorption spectrum give more insight into the dynamics of electronic structures.

Authors:
ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division
OSTI Identifier:
1529534
Alternate Identifier(s):
OSTI ID: 1515106
Report Number(s):
LA-UR-17-29749
Journal ID: ISSN 0031-9007; PRLTAO
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 122; Journal Issue: 20; Conference: APS March Meeting, Los Angeles, CA (United States), 5 March 2018; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English

Citation Formats

Lai, Chen-Yen, and Zhu, Jian-Xin. Ultrafast X-Ray Absorption Spectroscopy of Strongly Correlated Systems: Core Hole Effect. United States: N. p., 2019. Web. doi:10.1103/PhysRevLett.122.207401.
Lai, Chen-Yen, & Zhu, Jian-Xin. Ultrafast X-Ray Absorption Spectroscopy of Strongly Correlated Systems: Core Hole Effect. United States. doi:10.1103/PhysRevLett.122.207401.
Lai, Chen-Yen, and Zhu, Jian-Xin. Wed . "Ultrafast X-Ray Absorption Spectroscopy of Strongly Correlated Systems: Core Hole Effect". United States. doi:10.1103/PhysRevLett.122.207401.
@article{osti_1529534,
title = {Ultrafast X-Ray Absorption Spectroscopy of Strongly Correlated Systems: Core Hole Effect},
author = {Lai, Chen-Yen and Zhu, Jian-Xin},
abstractNote = {Recently, ultrafast pump-probe spectroscopy has provided insightful information about the nonequilibrium dynamics of excitations in materials. In a typical experiment of time-resolved x-ray absorption spectroscopy, the systems are excited by a femtosecond laser pulse (pump pulse) followed by an x-ray probe pulse after a time delay to measure the absorption spectra of the photoexcited systems. We present a theory for nonequilibrium x-ray absorption spectroscopy in one-dimensional strongly correlated systems. The core hole created by the x ray is modeled as an additional effective potential of the core hole site, which changes the spectrum qualitatively. In equilibrium, the spectrum reveals the charge gap at half-filling and the metal-insulator transition in the presence of the core hole effect. Moreover, a pump-probe scheme is introduced to drive the system out of equilibrium before the x-ray probe. The effects of the pump pulse with varying frequencies, shapes, and fluences are discussed for the dynamics of strongly correlated systems in and out of resonance. The spectrum suggests that the driven insulating state has a metallic droplet around the core hole. The rich structures of the nonequilibrium x-ray absorption spectrum give more insight into the dynamics of electronic structures.},
doi = {10.1103/PhysRevLett.122.207401},
journal = {Physical Review Letters},
number = 20,
volume = 122,
place = {United States},
year = {2019},
month = {5}
}

Journal Article:
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This content will become publicly available on May 22, 2020
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