Structural transformations and phase transitions in real-time

Project Information

TRANSFORMER

Grant agreement ID: 788218

DOI

10.3030/788218

Project closed

EC signature date 4 June 2018

Start date 1 September 2018

End date 31 August 2024

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 2 471 749,00

EU contribution

€ 2 471 749,00

Coordinated by

FUNDACIO INSTITUT DE CIENCIES FOTONIQUES
Spain

Periodic Reporting for period 4 - TRANSFORMER (Structural transformations and phase transitions in real-time)

Reporting period: 2023-03-01 to 2024-08-31

Summary of the context and overall objectives of the project

TRANSFORMER project aims to understand quantum interactions between carriers and nuclei, which are crucial for processes like chemical reactions, energy flow in solar cells, and electronic device efficiency. As global energy demands rise, with 10% of energy used for electronics and 14% by the chemical industry, new strategies are urgently needed. TRANSFORMER addresses these challenges by focusing on real-time electron-nuclear dynamics using laser-induced electron diffraction(LIED) and attosecond soft-x-ray spectroscopy(asXANES). These techniques explore molecular evolution, electron-hole interactions, and energy dissipation, key to improving energy efficiency and reducing quantum decoherence. To tackle these challenges, TRANSFORMER focuses on real-time electron-nuclear dynamics during molecular transformations and phase transitions using two pioneering techniques: LIED and asXANES. These methods allow for deeper exploration of how molecular structures evolve, how electrons and holes interact, and how energy dissipates into materials, processes that are vital to understanding and controlling electronic circuit noise and quantum decoherence. The project was structured around three objectives: O1 focused on using LIED for space-time imaging of molecules, O2 aimed at real-time extraction of electronic and nuclear information, and O3 targeted molecular isomerization and phase transitions. The third objective was modified, leading to breakthroughs in topological phase transitions and light-wave control over valleytronics, resulting in a patent application(J. Biegert, I. Tyulnev, J. Poborska, V. Lenard, M. Ivanov, O. Smirnova, “Method for valleytronics in bulk materials” EP23382921.7)

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

TRANSFORMER project has been a resounding success, as reflected in its strong publication record. Although the pandemic caused delays, we adapted effectively. The groundwork in O1 and O2 was largely completed, and adjusting our target systems during research led to even greater insights and high-profile results.
O1 focused on pushing the limits of LIED to capture space-time images of single molecules. This was a crucial step in exploring quantum systems at new space-time scales. Through various experiments, we proved we could image the positions of atoms in a single molecule using just one attosecond electron pulse. In O1.1 we demonstrated that even neutral molecules could be imaged despite ionization and assessed how ionization affects bond detection accuracy. We also controlled electron movements during imaging, reducing uncertainty to the attosecond scale, and developed a new method to extract molecular structures. In O1.2 we expanded LIED’s application to more complex, dynamic molecules, utilizing machine learning to identify structures, including chiral molecules.
O2 we tackled the challenge of simultaneously measuring both electron and nuclear movements, essential for understanding quantum physics. We imaged the hydrogen molecule(H2) during tunneling ionization, tracking electron exit points and nuclear changes. This was the first time both electron and nuclear movements were imaged together. Another major breakthrough(O2.2) involved combining XANES and EXAFS with attosecond X-rays, offering unprecedented detail on electron and nuclear structures. This helped answer key questions about electron scattering in materials like graphite and how energy flows within the material, crucial for understanding processes like polymerization in the chemical industry.
O3 combined our findings to address quantum phase transitions, where electron and nuclear movements are tightly coupled. In O3.1 we applied LIED to study molecular phase transitions in both simple and complex molecules, developing new imaging techniques using machine learning. In O3.2 we used advanced X-ray and harmonic spectroscopy to explore electronic and structural phase transitions in solids. Key breakthroughs included the first optical imaging of quantum phase transitions in high-temperature superconductors and the pioneering control of topological phase transitions, leading to a patent for a novel method in valleytronics.
In summary, the TRANSFORMER project exceeded its ambitious goals, leading to groundbreaking discoveries across quantum dynamics, phase transitions, and imaging techniques. These achievements have had wide-reaching impact, generating high-impact publications and establishing cutting-edge methodologies that will drive future advancements in science and technology with near-immediate applications.

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)

In pursuing O1 we set new standards in our LIED technique, advancing quantum dynamics into unexplored space-time domains of correlated quantum systems. Through extensive experimentation, we demonstrated the ability to image atomic positions within a single molecule using a single attosecond electron wavepacket.
Within O1.1 we successfully imaged neutral molecules with LIED, even under ionization, as documented in publications like Proc. Nat. Acad. Sci. and Rep. Prog. Phys. We also examined how ionization affects bond detection and evaluated the limits of quantum recollision, collaborating with the groups of Dudovich(Weizmann) and Bauer(Rostock). Our work resolved debates over the quantum trajectory contributions to LIED imaging and reduced temporal uncertainty to the attosecond regime. Additionally, we developed a method for extracting molecular structures from LIED data, proving its validity across different molecular systems.
In O1.2 we extended LIED imaging to complex and dynamic molecular systems, employing machine learning to identify the structures of highly complex and chiral molecules.
O2 achieved simultaneous electron and nuclear coordinate measurements. In O2.1 we imaged the H2 molecule during tunneling ionization, tracking the tunnel exit in momentum space and linking it to real space, while also monitoring changes in the nuclear wave packet. This marks the first imaging of a correlated electron-nuclear wavepacket, with a forthcoming publication.
O2 yielded groundbreaking advancements, using attosecond soft-X-ray pulses to extract electronic and nuclear information. This deepened our understanding of XANES and EXAFS, particularly in graphite, solving key questions about electron scattering and its lattice coupling. This research also provided insight into light absorption, electron/hole excitation, and phonon coupling—key steps in polymerization important for the chemical industry.
O3 integrated previous outcomes to tackle quantum phase transitions, where electronic and nuclear couplings challenge current methods. In O3.1 we used LIED to study molecular phase transitions, from simple triatomic species to complex chiral systems, developing new imaging methods using sparsity and machine learning for structure identification.
O3 saw remarkable progress. We employed attosecond X-ray and harmonic spectroscopy to disentangle electronic and structural phase transitions in solids. Highlights include optical imaging of quantum phase transitions in high-Tc superconductors and the first lightwave control of a topological phase transition, leading to valleytronics independent of material properties. This work resulted in a patent application for a novel method in valleytronics in bulk materials(EP23382921.7).
In conclusion, the project exceeded its ambitious goals, achieving significant breakthroughs in quantum dynamics, imaging, and phase transitions, made possible by TRANSFORMER grant.

brief overview of new results

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