We are part of the Service of Condensed Matter Physics (SPEC) in the IRAMIS institute of the French Atomic Energy and Alternative Energies Authority (CEA). Our research focuses on the study of the electronic and chemical structure of functional oxide surfaces, interfaces and films. To do so we employ a wide array of photoemission-based surface analysis techniques such as XPS, HAXPES, ARPES and PEEM as well as electron probes such as LEEM.
Our experimental work is done in both laboratory and synchrotron environments. We attach a lot of importance in building lasting collaborations with groups who are expert in epitaxial thin film growth, complementary experimental analysis techniques, device applications, micro and nanoelectronics technology, modelling and simulations.
News
The IEEE Eastern Europe Ferroelectric Symposium 2026 took place in Riga, Latvia, from June 1–4, 2026, attracting over 100 scientists worldwide. Organised by the Institute of Solid State Physics, University of Latvia, and sponsored by the IEEE UFFC Society, the programme featured 5 plenary talks, 22 invited lectures, 40 oral presentations, and 34 posters covering experimental and theoretical ferroelectrics research, with growing emphasis on AI and machine learning for microscopy and rapid materials discovery.
LENSIS Lab (SPEC, CEA Saclay) was well represented By Dr. Somnath Kale presenting his work on multilevel polarization switching in ferroelectric hafnium thin films and devices within the Ferro4EdgeAI framework.
L. Pérez Ramírez work on in situ HAXPES characterization of all-solid-state batteries (ASSBs) has just been published in Materials Today Communications. This article assesses the interfacial stability between β-Li3PS4 (LPS) solid state electrolyte and deposited lithium metal using in situ hard X-ray photoemission spectroscopy (HAXPES) approach. We show that the introduction of a 4 nm-thick Al2O3 interlayer grown by Atomic Layer Deposition (ALD) enhances the interfacial stability by mitigating undesirable side reactions. By comparing the two systems, LPS /Li and LPS/Al2O3/Li, we highlight the importance of interface engineering in solid-state batteries, particularly through protective coatings like Al2O3 made by ALD, which can enhance the stability of sulfide-based solid electrolytes against lithium metal.
Congratulations to our former PhD student, Tom Iung, for having successfully defending his thesis the past 21 of April. His subject based on “Hafnia-based ferroelectric field-effect transistor stacks: correlations between physical properties and device performances” was conjointly supervised by Nick Barrett (CEA) and Mickael Gros-Jean (STMicroelectronics). The discussions with a highly distinguished international jury were certainly fruitful and they contribute to the rigorousness of the work in our team.
The Novel High-k workshop (https://www.namlab.com/high-k-workshop-2026-march-24-25th) was held from March 24th to 26th at NaMLab in Dresden, Germany. The 20th anniversary of the discovery of ferroelectric doped HfO2 was celebrated by 36 oral presentations, ranging from theoretical and experimental studies on ferroelectricity in HfO2 to device applications of ferroelectric doped HfO2.
This year over 14000 scientists came together for the APS Global Physics summit held in Denver, Colorado, USA from 15th-19th March 2026 (https://summit.aps.org/).
Determination of the oxygen vacancy (VO) distribution within ultra-thin film ferroelectric hafnia (HfO2)-based devices is crucial to engineering optimal properties for non-volatile memory and logic devices. So far, x-ray photoelectron spectroscopy (XPS) combined with Ar+ ion sputtering has been the predominantly used approach for quantifying the VO concentration. Here, we show that using Ar+ ion sputtering to depth-profile the hafnia-based film affects film chemistry and can introduce errors in VO estimation by up to an order of magnitude.
As a result, the method should be approached with more caution. This paper demonstrates that non-destructive, hard x-ray photoemission (HAXPES) using synchrotron radiation ought to be favored. In addition, we show that reliable, quantitative evaluation of the physical chemistry is compromised by surprising and commonplace mistakes in parameters used for Hf 4f core-level spectral analysis. Third, a widespread assignation of one of the O 1s core-level peak components to the presence of VO is erroneous and leads to further errors in the measurement of VO concentration. The conclusions are supported by careful comparison between XPS and HAXPES experimental results and first principles calculations. We provide clear indications for reliable analysis and interpretation of the photoemission data, which should allow progress in materials engineering of ferroelectric devices.
More than 130 scientists took part in the 2026 edition of the 37th annual workshop on Fundamental Physics of Ferroelectric (https://www.materialsbydesign.org/ferro2026), in Tours, France from 2nd-5th February. 58 oral and 56 poster presentations covered a wide range on the physics of ferroelectricity and related phenomenon, with both experimental and theoretical approaches.
Jayshree Dadheech, Lucía Pérez Ramírez and Akash Mhase (INL Lyon) recently conducted hard xray photoelectron spectroscopy (HAXPES) experiments on the GALAXIES beamline at the SOLEIL synchrotron (Saint Aubin, France).
This beamtime was utilized to investigate the effect of Ta and TaOx interlayers on the interfacial chemistry of a reference stack TiN/Hf0.5Zr0.5O2/TiN and analyze their impact on the oxygen vacancy concentrations. Two batches with different Hf0.5Zr0.5O2 (HZO) thickness (6.7nm and 11.4nm) were investigated. These interlayer samples were fabricated using radio frequency sputtering by Akash Mhase, Sara Gonzalez at Institut des nanotechnologies de Lyon.
Major projects
3εFerro
Energy Efficient Embedded Non-volatile Memory & Logic based on Ferroelectric Hf(Zr)O2
H2020 grant agreement 780302
HREELM
High resolution electron energy loss microscopy : production of a monochromatic electron gun at low energy.
Collaboration CEA-CNRS-University Paris Saclay