Rashba spin-orbit coupling in infinite-layer nickelate films on SrTiO3(001) and KTaO3(001)
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arXiv
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| Format: | Preprint |
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2023
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| _version_ | 1866917561616039936 |
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| author | Geisler, Benjamin |
| author_facet | Geisler, Benjamin |
| contents | The impact of spin-orbit interactions in NdNiO2/SrTiO3(001) and NdNiO2/KTaO3(001) is explored by performing density functional theory simulations including a Coulomb repulsion term. Polarity mismatch drives the emergence of an interfacial two-dimensional electron gas in NdNiO2/KTaO3(001) involving the occupation of Ta $5d$ conduction-band states, which is twice as pronounced as in NdNiO2/SrTiO3(001). We identify a significant anisotropic $k^3$ Rashba spin splitting of the respective $d_{xy}$ states in both systems that results from the broken inversion symmetry at the nickelate-substrate interface and exceeds the width of the superconducting gap. In NdNiO2/KTaO3(001), the splitting reaches 210 meV, which is comparable to Bi(111) surface states. At the surface, the Ni $3d_{x^2-y^2}$-derived states exhibit a linear Rashba effect with $α_\text{R} \sim$ 125 meV Å, exemplifying its orbital selectivity. The corresponding Fermi sheets present a reconstructed circular shape due to the electrostatic doping, but undergo a Lifshitz transition towards a cuprate-like topology deeper in the film that coincides with a realignment of their spin texture. These results promote surface and interface polarity as interesting design parameters to control spin-orbit physics in infinite-layer nickelate heterostructures. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2303_00717 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Rashba spin-orbit coupling in infinite-layer nickelate films on SrTiO3(001) and KTaO3(001) Geisler, Benjamin Superconductivity Materials Science The impact of spin-orbit interactions in NdNiO2/SrTiO3(001) and NdNiO2/KTaO3(001) is explored by performing density functional theory simulations including a Coulomb repulsion term. Polarity mismatch drives the emergence of an interfacial two-dimensional electron gas in NdNiO2/KTaO3(001) involving the occupation of Ta $5d$ conduction-band states, which is twice as pronounced as in NdNiO2/SrTiO3(001). We identify a significant anisotropic $k^3$ Rashba spin splitting of the respective $d_{xy}$ states in both systems that results from the broken inversion symmetry at the nickelate-substrate interface and exceeds the width of the superconducting gap. In NdNiO2/KTaO3(001), the splitting reaches 210 meV, which is comparable to Bi(111) surface states. At the surface, the Ni $3d_{x^2-y^2}$-derived states exhibit a linear Rashba effect with $α_\text{R} \sim$ 125 meV Å, exemplifying its orbital selectivity. The corresponding Fermi sheets present a reconstructed circular shape due to the electrostatic doping, but undergo a Lifshitz transition towards a cuprate-like topology deeper in the film that coincides with a realignment of their spin texture. These results promote surface and interface polarity as interesting design parameters to control spin-orbit physics in infinite-layer nickelate heterostructures. |
| title | Rashba spin-orbit coupling in infinite-layer nickelate films on SrTiO3(001) and KTaO3(001) |
| topic | Superconductivity Materials Science |
| url | https://arxiv.org/abs/2303.00717 |