Interfacial charge transfer and persistent metallicity of ultrathin SrIrO3/SrRuO3 heterostructures

Jocienne N Nelson; Nathaniel J Schreiber; Alexandru B Georgescu; Berit H Goodge; Brendan D Faeth; Christopher T Parzyck; Cyrus Zeledon; Lena F Kourkoutis; Andrew J Millis; Antoine Georges; Darrell G Schlom; Kyle M Shen

doi:10.1126/sciadv.abj0481

Interfacial charge transfer and persistent metallicity of ultrathin SrIrO₃/SrRuO₃ heterostructures

Sci Adv. 2022 Feb 4;8(5):eabj0481. doi: 10.1126/sciadv.abj0481. Epub 2022 Feb 4.

Authors

Jocienne N Nelson¹, Nathaniel J Schreiber², Alexandru B Georgescu^{3

4}, Berit H Goodge⁵, Brendan D Faeth¹, Christopher T Parzyck¹, Cyrus Zeledon², Lena F Kourkoutis^{5

6}, Andrew J Millis^{3

7}, Antoine Georges^{3

8

9

10}, Darrell G Schlom^{2

6

11}, Kyle M Shen^{1

6}

Affiliations

¹ Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA.
² Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.
³ Center for Computational Quantum Physics, Flatiron Institute, New York, NY 10010, USA.
⁴ Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA.
⁵ School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA.
⁶ Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, USA.
⁷ Department of Physics, Columbia University, New York, NY 10027, USA.
⁸ Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France.
⁹ CPHT, CNRS, Ecole Polytechnique, IP Paris, F-91128 Palaiseau, France.
¹⁰ DQMP, Universitè de Genéve, 24 quai Ernest Ansermet, CH-1211 Genéve, Suisse.
¹¹ Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489 Berlin, Germany.

Abstract

Interface quantum materials have yielded a plethora of previously unknown phenomena, including unconventional superconductivity, topological phases, and possible Majorana fermions. Typically, such states are detected at the interface between two insulating constituents by electrical transport, but whether either material is conducting, transport techniques become insensitive to interfacial properties. To overcome these limitations, we use angle-resolved photoemission spectroscopy and molecular beam epitaxy to reveal the electronic structure, charge transfer, doping profile, and carrier effective masses in a layer-by-layer fashion for the interface between the Dirac nodal-line semimetal SrIrO₃ and the correlated metallic Weyl ferromagnet SrRuO₃. We find that electrons are transferred from the SrIrO₃ to SrRuO₃, with an estimated screening length of λ = 3.2 ± 0.1 Å. In addition, we find that metallicity is preserved even down to a single SrIrO₃ layer, where the dimensionality-driven metal-insulator transition typically observed in SrIrO₃ is avoided because of strong hybridization of the Ir and Ru t_2g states.