Oxide Interfaces for Quantum Devices
Oxide Nanointerface Engineering and Study for Electronic Quantum Device
Tech Area / Field
- PHY-SSP/Solid State Physics/Physics
- INS-DET/Detection Devices/Instrumentation
- PHY-RAW/Radiofrequency Waves/Physics
8 Project completed
Senior Project Manager
Tyurin I A
Russian Academy of Sciences / Institute of Radioengineering and Electronics, Russia, Moscow
- Russian Academy of Sciences / Physical Technical Institute, Russia, St Petersburg
- Technical University of Denmark, Denmark, Copenhagen\nSeconda Universita degli Studi di Napoli, Italy, Napoli\nChalmers University of Technology, Sweden, Göteborg
Project summaryOxide materials and especially transition metal oxides aroused a large scientific and technological interest for their rich spectrum of physical properties, which encompasses superconductivity, ferromagnetism, ferroelectricity, semiconducting and metallic behavior. Strongly correlated electrons play important role in forming physical parameters of oxides. Such properties are present in compounds with the same crystal structure, allowing the engineering of new epitaxial multifunctional devices. Interfaces in such highly correlated systems are very complex due to the collective nature of electronic behavior and offer new application possibilities with respect to conventional semiconductors. Substantial progress was achieved during last few years in developing technique for growth of an epitaxial oxide films and heterostructures including alternating films of the perovskite-type oxides, however microstructure of the layers (and interfaces, especially) have to be substantially improved.
The project aims to design, investigate, control and exploit the properties of interfaces in and between isostructural functional oxides for the realization of new electronic devices. The project will be focused on selected interfaces in thin film and heterostructures made from oxides with different functional properties, such as dielectric and superconductors, magnetic and metallic oxides. The functional properties of interfaces originating by the proximity of layers with different physical properties will be thoroughly studied. Charge and spin transport across the interfaces as well as induction strain near the internal interfaces will be investigated in details.
In the project, 3 different typologies of interfaces, selected on the basis of the physical mechanism involved in their working, will be investigated: 1) internal interfaces, 2) artificial interfaces, 3) heterostructures.
Strain-induced phase separation with internal interfaces in the cuprate, manganite and other oxide films grown on mismatched substrate will be studied systematically. We plan to use properly designed biaxial mechanical stresses for spatial ordering of nanointerfaces inclusions of the antiferromagnetic stripe phases in the nanometer thick manganite and cuprate superconducting layers in epitaxial multilayer heterostructures. Dielectric spectroscopy will be used to investigate dynamics of electro- and magneto-transport parameters of conducting oxides films at the interfaces to the insulating layers in sweeping magnetic and electric fields. Response of resistivity (and its anisotropy) of the strained cuprate and manganite films on interplay of antiferromagnetic, magnetic and superconducting phases will be traced for strained films with in-plane ordered and non ordered inclusions of the stripe phases.
We will exploit the modification of the physical properties of epitaxial films and interfaces induced by artificially made defects in the lattice of substrate with the aim of developing novel high performing devices. Oxide epitaxial films will be formed by laser deposition or dc-sputtering at high-pressure over specifically misoriented bicrystal substrates, consisting either of two in-plane tilted monocrystals at the certain angles of the basal axis, or using the out-of-plane tilting of monocrystal parts of the substrate. The deposited epitaxial oxide film repeats the substrate’s crystal orientation and forms a bicrystal thin film structure (bicrystal junction) with atomic size artificial interface. Cuprate and manganite bicrystal junctions will be used for design of novel electronic devices for operation at extremely high frequencies, including the THz band. The understanding of high frequency dynamical properties, particularly the nonequilibrium fluctuation phenomena in nanostructured artificial interface remains a problem of a crucial importance. However, noise properties and nonlinear behavior at high frequencies were not properly addressed before. Thus, an important gap in the knowledge will be filled.
Promising multilayer hybrid and isomorphic heterostructures with different intermediate layers sandwiched between epitaxial cuprate films, manganites or ruthenates will be realized and extensively studied for their physical properties. Studies of field effects between ferroelectric and metal conducting films will allow us to extract important information about charge carrier density at the nanometer scale. The transport of charge across interfaces in heterostructure is one of the key processes in conventional electronics. In the case of oxide magnetic active the injection of spin may play a significant role. Aiming at development of spin-manipulated devices that could be exploiting in quantum computation we plan in-depth studies of processes with spin polarized quasiparticle injection. Hybrid structure with enhanced component of second harmonic in superconducting current-phase relation will be fabricated and experimentally investigated. Magnetic and electronic properties will be probed by transport measurements, local spectroscopy and microwave measurements.
In the final part of the project, we will tackle the realization of selected devices with new functionalities whose operation principle are based on the control of the engineered interfaces. This activity will represent the most perceptible output of the project. New devices will be fabricated by using microtechnology techniques and exploiting the precise manipulation of physical properties of interfaces on nanometer scale. The project activity is pided into 4 tasks: three of them are concern the RTD tasks while the fourth one is mainly oriented on application.
Task 1 – Internal interfaces in cuprates and manganites and their influence on metal –insulator (metal-superconductor) transition
Task 2 – Artificial bicrystal interfaces in oxides and their electron and spin transport properties.
Task 3 – Hybrid and isomorphic heterostructures of superconductors, antiferromagnetic, ferromagnetic ferroelectric and normal metals
Task 4 – Devices: novel oxide electronics devices for quantum computing elements, Josephson THz wave detectors, fast operating transition edge bolometer, superconducting quantum interference filters.
Leading Institution of the project is the Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Laboratory of Oxide Electronics, where different kinds of superconducting detectors of weak electromagnetic fields were investigated for more than 30 years, and the oxide film structures are investigated since 1986. A variety of devices with unique properties based on low-temperature (metallic) superconductors were designed, fabricated and tested. The latter achievements in the oxide-based device research are first fabrication of out-plane tilted bicrystal superconducting structure for microwave application and the first observation of tunable response on noise signal at 750- 970 GHz in self-pumping mixing mode at temperature 12.5 K. The laboratory has all the necessary technological equipment as well as measuring instruments for precision dc and microwave characterization of the superconducting devices. Sophisticated technique of growth and final preparation of high-quality bicrystal substrates, including the low-loss substrates of sapphire and NdGaO3 (NGO), has been developed in the institute. Special deposition technique with the use of CeO2 buffer layer has been also developed to obtain high-quality oxide films on sapphire substrates as well as metallization layer implementation has been used to decrease surface microwave losses of noble metals.
The other Participating Institution is the Ioffe Physico-Technical Institute, Laboratory of Thermoelectrics, which is involved into investigation of oxide electronic devices since 1986. The laboratory stuff is well known an activity in the field of growth and characterization of an epitaxial films and multilayers of the multi component materials which evaporate non-congruently. The laboratory is well equipped by evaporation technique designed for growth (quasi equilibrium conditions or abnormally high supersaturation) of thin layers of multicomponent materials. Special technique (based on dielectric spectroscopy) was developed to probe electronic configuration at the interfaces between conducting/superconducting electrodes and insulating layers.
Foreign Project Collaborators from Europe, USA and Canada have stable permanent scientific collaboration with IRE RAS and PTI RAS. It is planned to enlarge the collaboration in experimental and theoretical investigations, involving young scientists and graduated students into the research work. Foreign Collaborators will also provide an access to some unique equipment, which currently is not available in CIS Institutions but is necessary to achieve desired quality of the planned researches in fabrication and microwave testing of the oxide based devices.
It is expected that the project execution will give new knowledge of basic properties of oxide materials and interfaces as well as novel technologies which will result in the unique oxide devices for detection of weak electromagnetic fields and the development of qubits for super-high speed data aquasion. Other devices, which are very important for the modern cellular phone nets, are the oxide superconducting quantum interference filter amplifiers at GHz frequencies. At last, based on oxide-interfaces – the sub-mm wave devices to be delivered are the high-sensitive detectors for environmental control systems and radioastronomy.
Significant role in attainment of the project goals pertains to the weapon scientists involved. Their experience in such application as the missile guiding systems and systems for tracking missiles and other military objects will be used for civil needs under this project.
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