Demystifying Quantum Phenomena at Functional Oxide Interfaces

When and Where

Dec 1, 2023
8:00am - 8:30am

Hynes, Level 3, Room 301

Presenter

Y. Eren Suyolcu

Yu-Mi Wu

Nicolas Bonmassar

Gennady Logvenov

Peter van Aken

Co-Author(s)

Y. Eren Suyolcu^1,2,Yu-Mi Wu¹,Nicolas Bonmassar¹,Gennady Logvenov¹,Peter Van Aken¹

Max Planck Institute for Solid State Research¹,Cornell University²

Abstract

Y. Eren Suyolcu^1,2,Yu-Mi Wu¹,Nicolas Bonmassar¹,Gennady Logvenov¹,Peter Van Aken¹

Max Planck Institute for Solid State Research¹,Cornell University²

Quantum materials possess extraordinary properties making them highly promising for next-generation electronic devices and quantum information processing. Among these materials, transition metal oxide heterostructures provide a versatile playground for quantum phenomena, including high-temperature superconductivity, magnetism, and metal-to-insulator transition. The origin of these phenomena is the competition between different degrees of freedom, such as charge, orbital, and spin, which are interrelated with the crystal structure, the oxygen stoichiometry, and the doping dependence. Therefore, understanding the intricate structure-property relationship in these materials is crucial for harnessing their full potential. The unique combination of aberration-corrected scanning transmission electron microscopy (STEM) and oxide molecular beam epitaxy (MBE) techniques allows the engineering of novel interface properties with precise control at the atomic scale[1]. Combining different oxide layers through heterostructural design opens access to interface physics and leads to engineering interface properties, where the degrees of freedom can be artificially modified. In this talk, I will focus on complex oxide interfaces with extraordinary structural quality and properties. We designed cuprate–manganite interfaces using oxide MBE and focused on interface superconductivity compared to cuprate–cuprate interfaces[2–4] and tuning interfacial magnetism[5]. The interfaces are extensively probed with STEM techniques, including high-angle annular dark-field (HAADF) and annular bright-field (ABF) imaging, electron energy-loss spectroscopy (EELS), and energy-dispersive X-ray spectroscopy (EDXS). High-resolution STEM investigations provide crucial feedback to improve structural quality and a detailed understanding of the properties. Through different epitaxial designs, we demonstrate that (i) charge transfer and local magnetism can be tuned by epitaxial strain[5], (ii) sharper interfaces can be realized by pushing the interface superconductivity down to one monolayer thickness but with a cost of filamentary superconducting behavior[6] and, (iii) how superconductivity can be tuned via epitaxial integration of ultra-thin 214-manganate slabs[7]. Notably, our investigations further underline that the sharpness of interfaces requires a meticulous definition: Structurally perfect and coherent interfaces may exhibit dissimilar chemical sharpness, ascribed to the elemental intermixing that dominates the physical properties. In summary, our research showcases the remarkable potential of quantum materials and highlights the crucial role of STEM techniques in unraveling their properties and designing interfaces for next-generation electronic devices and quantum information processing systems[8,9]. References [1] Y. E. Suyolcu, G. Christiani, P. A. van Aken, G. Logvenov, J. Supercond. Nov. Magn. 2020, 33, 107. [2] Y. E. Suyolcu, Y. Wang, W. Sigle, F. Baiutti, G. Cristiani, G. Logvenov, J. Maier, P. A. van Aken, Adv. Mater. Interfaces 2017, 4, 1700737. [3] Y. E. Suyolcu, J. Sun, B. H. Goodge, J. Park, J. Schubert, L. F. Kourkoutis, D. G. Schlom, APL Mater. 2021, 9, 021117. [4] N. Bonmassar, G. Christiani, U. Salzberger, Y. Wang, G. Logvenov, Y. E. Suyolcu, P. A. van Aken, ACS Nano 2023. [5] Y.-M. Wu, Y. E. Suyolcu, G. Kim, G. Christiani, Y. Wang, B. Keimer, G. Logvenov, P. A. van Aken, ACS Nano 2021, 15, 16228. [6] Y. E. Suyolcu, Y.-M. Wu, G. Kim, G. Christiani, G. Logvenov, P. A. van Aken, 2023, submitted. [7] N. Bonmassar, G. Christiani, T. Heil, G. Logvenov, Y. E. Suyolcu, P. A. van Aken, Adv. Sci. 2023, 2301495. [8] I kindly acknowledge all precious scientists for their significant contributions to the work presented, especially Prof. D. G. Schlom, Prof. B. Keimer, Dr. G. Kim, and G. Cristiani. [9] This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement 823717 – ESTEEM3.