Molecular Quantum Spintronics

To move quantum physics toward real-world information and energy applications, our physics team builds solid-state devices containing nano-objects, and addresses their quantum properties using spintronics. Since molecules are practical entities to manipulate when controlling an atom’s quantum properties, we grow and locally characterize molecular films, before inserting them into spintronic structures thanks to unique nanotechnologies.

Spintronics is a subset of Electronics in which the electron’s quantum spin property is used to drive an electrical device’s response. Historically, spintronics has explored spin-polarized transport across ‘large’ entities: thin ferromagnetic films, and more recently mesoscopic objects (e.g. skyrmions). Prototypical spintronic devices called magnetic tunnel junctions consist in ferromagnetic electrodes separated by an ultrathin insulating spacer. These devices can be downscaled to just a few nm and have been industrialized (read heads for hard drives; robust, non-volatile, ultrafast memories; bio-inspired computing…).

We define ‘Quantum Spintronics’ as expressing the quantum properties of atoms/nanoobjects within a spintronic device’s operation. These nanoobjects are atoms, functional molecules, or even oxygen vacancies within the device’s spacer layer (e.g. a tunnel barrier).

Why do ‘quantum spintronics’? Come discover the platform’s several key advantages in crafting the quantum coherence environment of spin qubits using the solid-state physics of real-world spintronic devices, compared to established quantum technology platforms (e.g. NV- center in diamond). Since meso/macro-scale spintronics has already been industrialized, quantum spintronics represents a compelling platform to propel quantum technologies toward consumer applications.

To control the properties of quantum nanoobjects, including their coherence, our teams specializes in quantum properties that are borne by molecules, which are easier to manipulate than individual atoms when assembling a solid-state device. Research into Molecular Quantum Spintronics requires A) fundamental growth/characterization studies, for example into the emergent properties at the ferromagnetic metal/molecule interface, and B) technical advances beyond the state-of-the-art.

To do so, the team develops and operates an innovative research chain that comprises:

1) tools to grow and characterize metal/molecule heterostructures;
2) micro- and nano-technologies to make hybrid spintronic devices (partly using the STNano technological platform); Video: how we make vertical molecular nanojunctions.
3) electrical measurements benches under external stimuli (temperature, magnetic field, light). The team also uses synchrotron radiation to probe the electronic properties of these heterostructures, and to test devices in operando.

Our several research lines implement interdisciplinary research at the interfaces between magnetism, spintronics, quantum thermodynamics, ferroic orders, molecules, oxides.

Research Activities

Multifunctional devices

Integrating functional spacers, such as the ferroelectric property of molecules, into spintronic devices is a means of achieving a multifunctional device, i.e. a device whose state (e.g. resistance) depends on a history of external stimuli (electric field, light, temperature, magnetic field, etc…). This targets Information and Communication Technologies.

Energy Harvesting

Our team is developping a new method to harvest the thermal fluctuations of ambient temperature using spintronics. Our devices integrate the paramagnetic centers of oxide and molecular compounds into spintronic devices that also comprise electrodes that select a spin channel for transport. This latter feature is accomplished using so-called spinterfaces (see below). See www.spinengine.tech for more details.

In the news

Several authors of the Adv. Mater. 2022 paper on energy harvesting discuss how the paper came about, and its portency, in this podcast (in french).

We published a first quantum theory of a two-cycle quantum spintronic engine that harvests vacuum fluctuation energy and bosonic drive energy in the form of a directed electrical current. Phys. Rev. B 109, 165432 (2024).

We call on atomic electronic physicists to help deepen our understanding of the quantum spintronic engine. npj Quantum Info. 9, 25 (2023).

We’ve reproduced our prior observation of spontaneous electrical power output on nine molecular spintronic devices. This ‘quantum spintronic engine’ utilizes magnetic exchange coupling between phthalocyanine molecules, and its strokes can reach ~100THz. A magnetoresistance of 770% is observed — a record for molecular spintronics. Adv. Mater. 34 2206688 (2022).

We’ve observed the robust reversibility of ferroelectricity in croconic acid molecular films. Nanoscale 13 19466 (2021)

We developed a novel nanotechnological process to study spin-polarized transport across a molecular spin chain within a solid-state device. Electrically exciting the spin chain from its quantum ground state generates a specific magnetoresistance signal. This quantum encoding of information lays the groundwork for information transmission across the spin chain. Adv. Func. Mater. 2009467 (2021).  Savoir Magazine

The website www.spinengine.tech describes the concept to spintronically harvest thermal fluctuations to the academic and general publics.

We reported spontaneous electrical power generation from a single spintronic device at room temperature. In this ‘spin engine’, the thermal fluctuations of paramagnetic centers are spintronically harvested. In the process, we demonstrated that the current flowing across the ‘spinterface’ is highly spin-polarized. Commun. Phys., 2 116 (2019). CNRS News. , Unistra News. , www.spinengine.tech

We factually demonstrated that the spin crossover molecular property is involved in electrical transport, thanks to synchrotron-grade in operando experiments. ACS Appl. Mater. & Int., 10 31580 (2018). Soleil Highlight 2018.

We harnessed the chemical selectivity of synchrotron-grade X-ray absorption spectroscopy to probe the active atoms of a device in operation. Adv. Mater., 1606578 (2017).  CNRS News

We demonstrated how to electrically modulate the magnetism of the ferromagnet/molecule interface, aka the ‘spinterface’. Adv. Func. Mater., 1700259 (2017). Soleil Highlight 2017.

We reported the simplest method to achieve a highly spin-polarized current source: create an interface between a ferromagnet and carbon atoms. Carbon 87, 269 (2015). CNRS News.

Quantum Nano-objects

The ‘spinterface’

The interface between a ferromagnet a molecule can develop emergent properties that are nicknamed the ‘spinterface’. The spinterface exhibits a low density of highly localized and highly spin-polarized electronic states at the Fermi level.  We recently demonstrated that the current flowing across the spinterface is highly spin-polarized at room temperature. Thanks to these properties, the spinterface constitutes an essential building block to address the quantum spin states of other nano-objects within our spintronic devices.

Molecular spin chains

The formation of the spinterface can modify the electronic properties of the metal and molecule constituents. A ferromagnetic metal may see its magnetic anisotropy radically altered. A non-magnetic metal can become magnetic. The magnetization of the molecular interfacial layer can be extended into the molecular film by harnessing magnetic interactions between molecules. This allows the spinterface to stabilize the magnetization of paramagnetic spin chains borne by molecules. Here, we use planar phthalocyanine molecules with a central paramagnetic site. We are studying how to spintronically address the ground and excited states of these spin chains using molecular nanojunctions. These molecules are also used to study the spintronic harvesting of thermal fluctuations.

Spin crossover molecules

The central magnetic site of a spin crossover molecule can be switched from a low-spin to a high-spin electronic configuration using external stimuli (light, temperature, electric field…). This makes it a promising candidate to control a spintronic device’s performance. We demonstrated that this molecular functionality is factually involved in transport using a synchrotron-based operando experiment. The next step is to integrate this molecular class into spintronic nanojunctions. To do so, we are leveraging fundamental research (here and here) on achieving spinterfaces with a noble metal surface so as to not freeze the spin crossover molecular property.

Ferroelectric molecules

Since spin-polarized charge transfer underscores the formation of the spinterface, one may modify the spinterface properties using ferroelectric molecules. To increase this effect, our team is optimizing the structural properties of the spinterface using croconic acid molecules, and intends to integrate these spinterfaces within spintronic nanojunctions. This method of forming an artificial magnetoelectric resembles efforts in the correlated oxides community, but benefits from a large charge transfer that is localized at the interface, and obviates the need to consider the role of oxygen vacancy migration.

Oxygen vacancies & paramagnetic centers

Controlling oxygen vacancies in functional oxides toward next-generation electronics remains challenging. Our team is examining how oxygen vacancies in the ‘simple’ oxide MgO drive the spintronic performance of magnetic tunnel junctions. Our experimental and theoretical results indicate that single and double oxygen vacancies can explain the combination of high spintronic performance, low barrier heights and metallic conduction depending on the junction’s magnetic state. We are examining the impact of these nano-objects on spin-transfer torque, a linchpin physical effect for spintronic technologies. Filling these vacancies with C can promote paramagnetic centers, leading to spintronic energy harvesting.

Experimental Capabilities

Along the research chain: from growth & characterization to device processing to multifunctional measurements

Growth & Characterization

Hybrid multichamber cluster

Ultra-high vacuum (UHV) tool to deposit metal, molecules and oxides using sputtering and thermal evaporation. From 2025: sharp top molecule-metal interface using buffer-layer assisted growth of our top metallic electrode.

Heterostructure stacks used to make nanojunctions are grown here.

Multiprobe UHV station

Variable temperature Omicron UHV setup to perform local probe techniques (AFM, conducting AFM, MFM, PFM, STM) on surface and bilayers. Basic spinterface studies are performed here. From 2025: UHV interconnection with the ‘Hybrid’ cluster.

Spin-polarized electron reflectometry

A UHV setup to probe the spin-polarized electronic properties of single films and heterostructures. Basic spinterface studies are performed here.

Synchrotron techniques

Our team has the expertise to conduct synchrotron beamtime runs in which in-situ grown heterostructures are probed using x-Ray absorption, spin-polarized photoemission and STXM.

Device Processing

UV lithography

The team implements a resist- and solvent-based process to craft heterostructures into ~10-micron diameter pillars for magnetotransport measurements. The process is compatible with correlated oxides.

Nanobead processing

Since most molecules may degrade under exposure to solvents and resist, our team has developed a resist- and solvent-free technology that crafts entire heterostructures (thereby preserving UHV-quality interfaces) into vertical nanojunctions. This is a unique capability world-wide that we wish to collaboratively open to other teams. This is how the process works.

Multifunctional measurements

Multifunctional Bench

Our team has developed an electrical transport bench around a cryo-free cryostat with the following characteristics: T:10-350K, up to H=2T along or at an angle with the sample and the optical axis, cw and ns-pulsed lasers covering 200-2600nm; ns-resolved spectroscopic camera, ns-grade electrical signal/response.

V2TI electrical insert at Beamline DEIMOS, Synchrotron SOLEIL

Our team helped to develop an electrical insert on Beamline DEIMOS, Synchrotron SOLEIL. It is therefore possible to implement the chemical and magnetic sensitivity of X-ray absorption spectroscopy (XAS) on materials subjected to electrical polling (e.g. spinterfaces), or even on devices in operando.

Team Members

Professor, Magnetic Objects on the NanoScale (DMONS)Mebarek.Alouani@ipcms.unistra.fr
Tél: +33(0)3 88 10 70 06Bureau: 0008
Voir la page personnelle
Assistant professor, Magnetic Objects on the NanoScale (DMONS)benjamin.bacq-labreuil@ipcms.unistra.fr
Tél: +33(0)3 88 10 70 14Bureau: 0007
Assistant professor, Magnetic Objects on the NanoScale (DMONS)Samy.Boukari@ipcms.unistra.fr
Tél: +33(0)3 88 10 71 75Bureau: 1007
Senior Researcher, Magnetic Objects on the NanoScale (DMONS)Martin.Bowen@ipcms.unistra.fr
Tél: +33(0)3 88 10 68 88Bureau: 0011
Voir la page personnelle
Research Engineer, Magnetic Objects on the NanoScale (DMONS)Victor.Dacosta@ipcms.unistra.fr
Tél: +33(0)3 88 10 70 65Bureau: 1004
Voir la page personnelle
Research Engineer, Magnetic Objects on the NanoScale (DMONS)Benoit.Gobaut@ipcms.unistra.fr
Tél: +33(0)3 88 10 70 92Bureau: 0011
Voir la page personnelle
Research Engineer, Magnetic Objects on the NanoScale (DMONS)Loic.Joly@ipcms.unistra.fr
Tél: +33(0)3 88 10 72 57Bureau: 1008
Voir la page personnelle
Engineer, Magnetic Objects on the NanoScale (DMONS)Christophe.Kieber@ipcms.unistra.fr
Tél: +33(0)3 88 10 67 82Bureau: 0023
Researcher, Magnetic Objects on the NanoScale (DMONS)julie.lion@ipcms.unistra.fr
Bureau: 1016
PhD student, Magnetic Objects on the NanoScale (DMONS)ujjawal.rathore@ipcms.unistra.fr
Tél: +33(0)3 88 10 70 77Bureau: 1016
PhD student, Magnetic Objects on the NanoScale (DMONS)theo.robert2@ipcms.unistra.fr
Tél: /Bureau: 0006
PhD student, Magnetic Objects on the NanoScale (DMONS)aaron.wandhammer@ipcms.unistra.fr
Tél: /Bureau: 0006
Professor, Magnetic Objects on the NanoScale (DMONS)Wolfgang.Weber@ipcms.unistra.fr
Tél: +33(0)3 88 10 70 87, +33(0)3 88 10 70 02Bureau: 1048
Voir la page personnelle

Prior Members

Eric Beaurepaire, décédé en Avril 2018.
Jacek Arabski, retraite en 2020.

DJ Kim, Postdoc at U. Warwick
S. Shi, postdoc at U. Linkoping
R. Rakshit, Scientist at CSIR-National Physical Laboratory, India
S. Javaid, Researcher at Pakistan Institute of Nuclear Science & Technology
JB Beaufrand, private sector
F. Schleicher, engineer at IMEC
H. Jabbar, professor at U. Basrah, Iraq
V. Davesne, private sector
M. Gruber, researcher at U. Kiel, Germany
U. Halisdemir, postdoc at U. Twente, Netherlands
M. Studniarek, private sector
E. Urbain, private sector
K. Katcko, an engineer at IMEC

B. Chowrira, engineer at IMEC

L. Kandpal, postdoc Muduli group, New Delhi

Patents

– 04/2012 : SOURCE DE COURANT POLARISEE EN SPINS, M. Bowen, W. Weber, L. Joly, E. Beaurepaire, F. Scheurer, S. Boukari, M. Alouani, FR 2012/ 12 53564 & PCT/EP2013/057804 & WO2013156441A1.

– 04/2012 : DISPOSITIF INJECTEUR DE SPINS COMPORTANT UNE COUCHE DE PROTECTION EN SON CENTRE, M. Bowen, M. Alouani, S. Boukari, E. Beaurepaire, W. Weber, F. Scheurer, L. Joly, FR 2012/ 12 53569 & PCT/EP2013/057769 & WO2013156426A1.

– 11/2012 : KIT DE CONNEXION D’UN COMPOSANT MICROELECTRONIQUE CONTRE DES DECHARGES ELECTROSTATIQUES LORS DE SA CONNEXION A UN DISPOSITIF CONDUCTEUR, M. Bowen, B. Leconte, D. Spor, FR 2012/12 60606 & PCT/ EP2013073174 & WO2014072347 A1.

– 11/2012 : DISPOSITIF DE POMPAGE, COMPRENANT UN ENSEMBLE DE POMPES EN SERIES ET UN ELEMENT DE COMMUTATION COMMUN, M. Bowen, C. Kieber, S. Boukari, FR 2012/12 60672 & PCT/ EP2013073344 & WO2014072452A1.

– 08/2014: PROCESS OF DETECTION OF LIGHT AND ASSOCIATED DEVICE, M. Bowen, U. Halisdemir, F. Schleicher, S. Boukari, E. Beaurepaire, EP14180354 & EP 2982950 A1 & WO2016020243A1.

Recent publications :

[1]
X. Weng, M. Hennes, A. Juhin, P. Sainctavit, B. Gobaut, E. Otero, F. Choueikani, P. Ohresser, T. Tran, D. Hrabovsky, D. Demaille, Y. Zheng, F. Vidal, Strain-engineering of magnetic anisotropy in CoxNi1-x-SrTiO3/SrTiO3(001) vertically assembled nanocomposites, Physical Review Materials 6 (2022) 046001. https://doi.org/10.1103/PhysRevMaterials.6.046001.
[1]
R. Tuerhong, F. Ngassam, M. Alouani, J.-P. Bucher, When Molecular Dimerization Induces Magnetic Bi-Stability at the Metal-Organic Interface, Advanced Physics Research 2 (2023) 2200005. https://doi.org/10.1002/apxr.202200005.
[1]
J. Solano, Q. Rossi, J. Robert, M. Lenertz, Y. Henry, B. Gobaut, D. Halley, M. Bailleul, Unraveling the temperature-dependent spin-polarized electron transport in iron via spin-wave Doppler shift, Physical Review B 112 (2025) L140407. https://doi.org/10.1103/vh21-mhmv.
[1]
L. Poggini, E. Tancini, C. Danieli, A.L. Sorrentino, G. Serrano, A. Lunghi, L. Malavolti, G. Cucinotta, A.-L. Barra, A. Juhin, M.-A. Arrio, W. Li, E. Otero, P. Ohresser, L. Joly, J.P. Kappler, F. Totti, P. Sainctavit, A. Caneschi, R. Sessoli, A. Cornia, M. Mannini, Engineering Chemisorption of Fe4 Single-Molecule Magnets on Gold, Advanced Materials Interfaces 8 (2021) 2101182. https://doi.org/10.1002/admi.202101182.
[1]
R. Pasquier, K. Rassoul, M. Alouani, Inverse spin crossover in fluorinated Fe(1,10-phenanthroline)2(NCS) 2 adsorbed on Cu (001) surface, Computational Condensed Matter 32 (2022) e00735. https://doi.org/10.1016/j.cocom.2022.e00735.
[1]
R. Pasquier, M. Alouani, Calculated iron L2,3 x-ray absorption and x-ray magnetic circular dichroism of spin-crossover Fe(phen)2(NCS)2 molecules adsorbed on a Cu(001) surface, Physical Review B 108 (2023) 094423. https://doi.org/10.1103/PhysRevB.108.094423.
[1]
R. Pasquier, M. Alouani, On entropy driven spin crossover in pristine and fluorinated Fe(phenanthroline)2(NCS)2: Insight from DFT, Journal of Chemical Physics 163 (2025) 244105. https://doi.org/10.1063/5.0295368.
[1]
S. Pandey, T. Pin, S. Hettler, R. Arenal, C. Bouillet, T. Maroutian, J. Robert, B. Gobaut, B. Kundys, J.-F. Dayen, D. Halley, Proximity-Mediated Multi-Ferroelectric Coupling in Highly Strained EuO-Graphene Heterostructures, Advanced Materials (2025) 2417669. https://doi.org/10.1002/adma.202417669.
[1]
S. Mohapatra, W. Weber, B. Gobaut, M. Bowen, S. Boukari, V. Da Costa, Polarization Vector Canting in Croconic Acid Ferroelectric Nanoscopic Regions, Advanced Materials Technologies (2024) 2301257. https://doi.org/10.1002/admt.202301257.
[1]
S. Mohapatra, W. Weber, M. Bowen, S. Boukari, V. Da Costa, Toward accurate ferroelectric polarization estimation in nanoscopic systems, Journal of Applied Physics 132 (2022) 134101. https://doi.org/10.1063/5.0102920.
[1]
S. Mohapatra, S. Cherifi-Hertel, S.K. Kuppusamy, G. Schmerber, J. Arabski, B. Gobaut, W. Weber, M. Bowen, V. Da Costa, S. Boukari, Organic ferroelectric croconic acid: a concise survey from bulk single crystals to thin films, Journal of Materials Chemistry C 10 (2022) 8142–8167. https://doi.org/10.1039/D1TC05310H.
[1]
S. Mohapatra, E. Beaurepaire, W. Weber, M. Bowen, S. Boukari, V. Da Costa, Accessing nanoscopic polarization reversal processes in an organic ferroelectric thin film, Nanoscale 13 (2021) 19466–19473. https://doi.org/10.1039/d1nr05957b.
[1]
M. Lamblin, V. Da Costa, L. Joly, B. Chowrira, L. Petitdemange, B. Vileno, R. Bernard, B. Gobaut, S. Boukari, W. Weber, M. Hehn, D. Lacour, M. Bowen, MgO Tunneling Spintronics across Capacitively Coupled Atomic Clusters, Nano Letters 25 (2025) 18026–18035. https://doi.org/10.1021/acs.nanolett.5c03672.
[1]
M. Lamblin, M. Bowen, Quantum measurement spintronic engine powered by quantum coherence enhanced by bosonic catalysis, Physical Review B 109 (2024) 165423. https://doi.org/10.1103/PhysRevB.109.165423.
[1]
K. Katcko, E. Urbain, F. Ngassam, L. Kandpal, B. Chowrira, F. Schleicher, U. Halisdemir, D. Wang, T. Scherer, D. Mertz, B. Leconte, N. Beyer, D. Spor, P. Panissod, A. Boulard, J. Arabski, C. Kieber, E. Sternitzky, V. Costa, M. Hehn, F. Montaigne, A. Bahouka, W. Weber, E. Beaurepaire, C. Kubel, D. Lacour, M. Alouani, S. Boukari, M. Bowen, Encoding Information on the Excited State of a Molecular Spin Chain, Advanced Functional Materials 31 (2021) 2009467. https://doi.org/10.1002/adfm.202009467.
[1]
L.M. Kandpal, B. Taudul, E. Monteblanco, A. Kumar, K. Katcko, F. Schleicher, P. Gupta, S. Boukari, W. Weber, V. Da Costa, J.D. Costa, T. Bӧhnert, R. Ferreira, P. Freitas, M. Hehn, M. Alouani, P.K. Muduli, D. Lacour, M. Bowen, Oxygen vacancy-driven spin-transfer torque across MgO magnetic tunnel junctions, Npj Spintronics 3 (2025) 2. https://doi.org/10.1038/s44306-024-00067-8.
[1]
L. Joly, F. Scheurer, P. Ohresser, B. Kengni-Zanguim, J.-F. Dayen, P. Seneor, B. Dlubak, F. Godel, D. Halley, X-ray magnetic dichroism and tunnel magneto-resistance study of the magnetic phase in epitaxial CrVO x nanoclusters, Journal of Physics-Condensed Matter 34 (2022) 175801. https://doi.org/10.1088/1361-648X/ac4f5e.
[1]
V. Desbuis, D. Lacour, C. Tiusan, W. Weber, M. Hehn, Low-Energy Spin Manipulation Using Ferromagnetism, Annalen Der Physik 536 (2024) 2400226. https://doi.org/10.1002/andp.202400226.
[1]
V. Desbuis, D. Lacour, C. Tiusan, C. Vautrin, S. Migot, J. Ghanbaja, Y. Lu, W. Weber, M. Hehn, Manipulation of low-energy spin precession in a magnetic thin film by tuning its molecular field, Physical Review B 109 (2024) 024403. https://doi.org/10.1103/PhysRevB.109.024403.
[1]
V. Desbuis, D. Lacour, C. Tiusan, W. Weber, M. Hehn, sp- and d-band effects on secondary low-energy electron generation, Physical Review B 108 (2023) 214424. https://doi.org/10.1103/PhysRevB.108.214424.
[1]
B. Chowrira, L. Kandpal, M. Lamblin, F. Ngassam, C.-A. Kouakou, T. Zafar, D. Mertz, B. Vileno, C. Kieber, G. Versini, B. Gobaut, L. Joly, T. Ferté, E. Monteblanco, A. Bahouka, R. Bernard, S. Mohapatra, H. Prima Garcia, S. Elidrissi, M. Gavara, E. Sternitzky, V. Da Costa, M. Hehn, F. Montaigne, F. Choueikani, P. Ohresser, D. Lacour, W. Weber, S. Boukari, M. Alouani, M. Bowen, Quantum Advantage in a Molecular Spintronic Engine that Harvests Thermal Fluctuation Energy., Advanced Materials 34 (2022) e2206688. https://doi.org/10.1002/adma.202206688.
[1]
H. Bulou, L. Joly, J.-M. Mariot, F. Scheurer, Magnetism and Accelerator-Based Light Sources, 2021. https://doi.org/10.1007/978-3-030-64623-3.
[1]
M. Bowen, M. Lamblin, Implementing a Quantum Information Engine Using Spintronics, in: X. Bouju, C. Joachim (Eds.), Crossroad of Maxwell Demon, Springer Nature Switzerland, Cham, 2024: pp. 93–114. https://doi.org/10.1007/978-3-031-57904-2_5.
[1]
M. Bowen, Atom-level electronic physicists are needed to develop practical engines with a quantum advantage, NPJ Quantum Information 9 (2023) 1–3. https://doi.org/10.1038/s41534-023-00692-x.
[1]
M. Bowen, Encodage quantique par voie spintronique, Savoir(s) : le magazine d’information de l’université de Strasbourg (2021) 13. https://applications.unistra.fr/unistra/visionneuse/Savoirs/42/.
[1]
B. Bacq-Labreuil, B. Lacasse, A.-M.S. Tremblay, D. Sénéchal, K. Haule, Toward an Ab Initio Theory of High-Temperature Superconductors: A Study of Multilayer Cuprates, Physical Review X 15 (2025) 021071. https://doi.org/10.1103/PhysRevX.15.021071.
[1]
B. Bacq-Labreuil, C. Fawaz, Y. Okazaki, Y. Obata, H. Cercellier, P. Le Fevre, F. Bertran, D. Santos-Cottin, H. Yamamoto, I. Yamada, M. Azuma, K. Horiba, H. Kumigashira, M. d’Astuto, S. Biermann, B. Lenz, Universal Waterfall Feature in Cuprate Superconductors: Evidence of a Momentum-Driven Crossover, Physical Review Letters 134 (2025) 016502. https://doi.org/10.1103/PhysRevLett.134.016502.