Hydrodynamic electronics

Project Information

HYDROTRONICS

Grant agreement ID: 873028

DOI

10.3030/873028

Project closed

EC signature date 20 November 2019

Start date 1 December 2019

End date 31 May 2025

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 524 400,00

EU contribution

€ 506 000,00

Coordinated by

KARLSRUHER INSTITUT FUER TECHNOLOGIE
Germany

Periodic Reporting for period 2 - HYDROTRONICS (Hydrodynamic electronics)

Reporting period: 2023-06-01 to 2025-05-31

Summary of the context and overall objectives of the project

Advances in the fabrication of ultra-pure low-dimensional materials have led in recent years to the emergence of a new area of research – hydrodynamic electronics. This cutting-edge field investigates how electrons behave like a fluid in ultra-pure, low-dimensional materials, where collisions between electrons become the dominant force shaping their physical properties, thanks to modern technologies that allow for the routine manufacturing of such samples. This unique "fluid-like" behavior manifests as non-local, superballistic, and viscous transport of energy and electric charge. Following the immense success of graphene research, many novel two-dimensional materials are currently being investigated, aiming at potential applications in nanoelectronics, as well as energy conversion and storage. The past years have seen an explosion of interest, both experimental and theoretical, in the hydrodynamic effects in interacting electron systems in ultra-pure materials.
The HYDROTRONICS project pursued two primary aims:
• To develop a comprehensive framework for describing hydrodynamic charge and energy transport that can be fine-tuned to various material properties and experimental settings.
• To uncover new physics in novel materials through transport and optical measurements.

These aims were supported by a strong collaboration among experimental, theoretical, and computational groups, fostering an environment for new ideas and the development of early-stage researchers.
The specific research objectives of HYDROTRONICS included:
• Electronic hydrodynamics in novel materials, such as van der Waals heterostructures, twisted bilayer graphene, and Weyl semimetals.
• Nonlocal and nonlinear phenomena in electronic hydrodynamics, including 2D turbulence.
• Light-matter interaction, near-field optics, and coupling to external magnetic systems (e.g. in stacked layered devices).

Combining the microscopic and macroscopic methods to interacting electronic systems allowed for a unique perspective and yielded a powerful approach to transport phenomena that can be easily adapted to new materials and experimental settings, as they become accessible in the course of rapid technological progress. Strong collaboration between the groups involved in the project and its overall synergy allowed novel ideas to flourish, promoting a fertile environment in which early-stage researchers could develop their own paths and resolve the biggest issues in the field. Another important goal was a closer integration between the experimental, theoretical, and computational (software development) parts of the network, which will be an important element exposing practitioners in each area to cutting edge progress in the others.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

We have built foundations of a general hydrodynamic framework that allowed us to describe electrical and energy transport fine-tuned to the material properties and sample geometries, and, based on this approach, to investigate the physics of novel materials. Combining the microscopic and macroscopic methods to study correlated systems in real materials yielded a powerful approach that proved to be easily adapted to new experimental settings. The achievements range from fundamental science to applications that offer novel functionalities of electronic devices. Networking within the project has provided us with a strong link between theory, experiment, and software development, owing to the complementary expertise of the partners involved. Among the main project results achieved are the theoretical and experimental findings concerning the hydrodynamic behavior of electronic fluids in ultra-pure graphene samples and van der Waals heterostructures, as well as novel inputs to our understanding of turbulence in terms of information theory. The project also developed a basis for a microscopic description of novel (mainly two-dimensional) materials and structures in the presence of external driving (e.g. in the context of light-matter interaction), as well as of various magnetic and superconducting properties thereof.
HYDROTRONICS has produced over 100 scientific publications, primarily peer-reviewed journal articles, showcasing the relevance of the project's achievements. These results have also been presented at numerous international scientific conferences and meetings, including prominent events like the APS March Meetings and the HYDROTRONICS conferences.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

HYDROTRONICS has already made significant progress beyond the state of the art in hydrodynamic electronics. The HYDROTRONICS Consortium has established a robust framework, achieved notable results, and has extensively published. Notable results were achieved across all research objectives of HYDROTRONICS, as exemplified in the list of selected most recent project achievements below:

1. Electronic Hydrodynamics in Novel Materials:
A general kinetic theory for non-local electrodynamics in two and three dimensions, applicable to various Fermi surface shapes, was developed and compared with experimental data
2. Nonlocal and Nonlinear Phenomena:
We found extreme electron-hole drag and negative mobility in graphene's Dirac plasma near room temperature, highlighting strong interactions, although competing scattering mechanisms can limit true hydrodynamic flow.
3. Light-Matter Interaction, Near-Field Optics, and Magnetic Coupling:
We explored Floquet engineering to create spatially dependent light-matter interactions in graphene, leading to scalable zero-bias photocurrents by manipulating laser configurations.

The project's impacts are far-reaching and include advancements in nanoelectronics, as well as scientific knowledge that supports the development of early-stage researchers. The original concept of HYDROTRONICS focused on understanding the mutual interaction between electronic, magnetic, and optical properties. This enables the design of novel devices where electric and/or magnetic properties can be controlled by light or electronic means. For instance, research on light-matter interaction in the hydrodynamic regime aimed to control electric circuits through light illumination, while investigations on van der Waals heterostructures with magnetic layers allowed electronic control of macroscopic magnetization. The potential of 2D systems and van der Waals heterostructures enables the creation of artificial materials with unprecedented combinations of properties, reshaping such research fields as plasmonics and optoelectronics. It is particularly impactful for experimental and technological activities.
From a socio-economic perspective, the advancements in hydrodynamic electronics hold promise for transforming nanoelectronics and energy conversion/storage technologies, leading to innovative applications with improved efficiency and performance. On a wider societal scale, the project contributed to the scientific knowledge base, promoting idea exchange, encouraging further research, and nurturing the growth of early-stage researchers. The publication of high-profile peer-reviewed articles inspired intense theoretical and experimental research efforts beyond the project, validating and extending its findings. Furthermore, the project's emphasis on collaboration and integration across disciplines sets a precedent for future endeavors, highlighting the value of multidisciplinary approaches and promoting environments for industrial spin-offs, further supporting the project’s socio-economic impact.

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