Enhanced orbital anisotropy through the proximity to a SrTi O3 layer in the perovskite iridate superlattices
(2021) In Physical Review B 104(7).- Abstract
We have used angle-dependent soft x-ray absorption spectroscopy (XAS) at the O K edge and first-principles calculations to investigate the electronic structures of iridate-based superlattices (SrIrO3)m/(SrTiO3) (m=1, 2, 3, and ∞). We focus on the pre-edge Ir 5d t2g-O 2p orbital hybridization feature in the XAS spectra. By varying the measurement geometry relative to the incident photon polarization, we are able to extract the dichroic contrast and observe the systematic increase in the anisotropy of Ir 5d orbitals as m decreases. First-principles calculations elucidate the orbital anisotropy coming mainly from the enhanced out-of-plane compression of IrO6 octahedra in the SrIrO3 layers that are adjacent to the inserted SrTiO3 layers. As... (More)
We have used angle-dependent soft x-ray absorption spectroscopy (XAS) at the O K edge and first-principles calculations to investigate the electronic structures of iridate-based superlattices (SrIrO3)m/(SrTiO3) (m=1, 2, 3, and ∞). We focus on the pre-edge Ir 5d t2g-O 2p orbital hybridization feature in the XAS spectra. By varying the measurement geometry relative to the incident photon polarization, we are able to extract the dichroic contrast and observe the systematic increase in the anisotropy of Ir 5d orbitals as m decreases. First-principles calculations elucidate the orbital anisotropy coming mainly from the enhanced out-of-plane compression of IrO6 octahedra in the SrIrO3 layers that are adjacent to the inserted SrTiO3 layers. As m decreases, the increased volume fraction of these interfacial SrIrO3 layers and their contact with the SrTiO3 layers within the (SrIrO3)m/(SrTiO3) supercell lead to enhanced orbital anisotropy. Furthermore, the tilt and rotation of IrO6 octahedra are shown to be essential to understand the subtle orbital anisotropy in these superlattices, and constraining these degrees of freedom will give an incorrect trend. Our results demonstrate that the structural constraint from the inserted SrTiO3 layers, in addition to other electronic means such as polar interface and charge transfer, can serve as a knob to control the orbital degree of freedom in these iridate-based superlattices.
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- author
- Huang, Wencheng ; Liu, Wanling ; Shao, Yu Cheng ; Feng, Xuefei ; Zhang, Nian ; Fu, Jiamin ; Lee, Jenn Min LU ; Shen, Dawei ; Chuang, Yi De and Liu, Xiaosong
- organization
- publishing date
- 2021-08-15
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Review B
- volume
- 104
- issue
- 7
- article number
- 075156
- publisher
- American Physical Society
- external identifiers
-
- scopus:85114187855
- ISSN
- 2469-9950
- DOI
- 10.1103/PhysRevB.104.075156
- language
- English
- LU publication?
- yes
- id
- bf4692d3-268d-4307-b536-2c624908a7c8
- date added to LUP
- 2021-10-07 10:09:31
- date last changed
- 2025-04-04 14:27:10
@article{bf4692d3-268d-4307-b536-2c624908a7c8,
abstract = {{<p>We have used angle-dependent soft x-ray absorption spectroscopy (XAS) at the O K edge and first-principles calculations to investigate the electronic structures of iridate-based superlattices (SrIrO3)m/(SrTiO3) (m=1, 2, 3, and ∞). We focus on the pre-edge Ir 5d t2g-O 2p orbital hybridization feature in the XAS spectra. By varying the measurement geometry relative to the incident photon polarization, we are able to extract the dichroic contrast and observe the systematic increase in the anisotropy of Ir 5d orbitals as m decreases. First-principles calculations elucidate the orbital anisotropy coming mainly from the enhanced out-of-plane compression of IrO6 octahedra in the SrIrO3 layers that are adjacent to the inserted SrTiO3 layers. As m decreases, the increased volume fraction of these interfacial SrIrO3 layers and their contact with the SrTiO3 layers within the (SrIrO3)m/(SrTiO3) supercell lead to enhanced orbital anisotropy. Furthermore, the tilt and rotation of IrO6 octahedra are shown to be essential to understand the subtle orbital anisotropy in these superlattices, and constraining these degrees of freedom will give an incorrect trend. Our results demonstrate that the structural constraint from the inserted SrTiO3 layers, in addition to other electronic means such as polar interface and charge transfer, can serve as a knob to control the orbital degree of freedom in these iridate-based superlattices.</p>}},
author = {{Huang, Wencheng and Liu, Wanling and Shao, Yu Cheng and Feng, Xuefei and Zhang, Nian and Fu, Jiamin and Lee, Jenn Min and Shen, Dawei and Chuang, Yi De and Liu, Xiaosong}},
issn = {{2469-9950}},
language = {{eng}},
month = {{08}},
number = {{7}},
publisher = {{American Physical Society}},
series = {{Physical Review B}},
title = {{Enhanced orbital anisotropy through the proximity to a SrTi O3 layer in the perovskite iridate superlattices}},
url = {{http://dx.doi.org/10.1103/PhysRevB.104.075156}},
doi = {{10.1103/PhysRevB.104.075156}},
volume = {{104}},
year = {{2021}},
}