HERO PROJECT: Hidden Entangled and Resonating Orders

Hidden, Entangled and Resonating Orders

To further the understanding of quantum properties of materials, four expert scientists have been awarded a 14 million Euro ERC Synergy Grant, administered by the European Research Council (ERC) of the European Union.

The team consists of three scientists in Switzerland and one in Sweden: Gabriel Aeppli at PSI, Henrik Rønnow at EPFL, Nicola Spaldin at ETH Zurich and Alexander Balatsky at Nordita, Stockholm University. Their joint research aims to uncover hidden quantum properties in known materials, meaning properties that could not be seen by methods employed up to now.

The researchers called their joint research project HERO which stands for Hidden, entangled and resonating orders – all of which are important quantum properties they will look at in order to discover possible materials of the future. To achieve this, the expert scientists will use the several large research facilities at PSI for complementary investigations and exploit the computing power of the Swiss National Supercomputing Centre CSCS of the ETH Zurich in Lugano for data processing and theoretical calculations.

The HERO project is half a way through and significant progress has been already achieved including:

  • The development of a scheme to create pairs of exact copies of XFEL pulses with controlled time spacings  as well as the demonstration of soft X-ray side-band formation via optical seeding at SwissFEL. These accomplishments will lead to the ability to measure the more complex electronic correlations associated with the hidden order which is the main theme of this project.
  • The development of the theoretical methodology for the understanding of magnetoelectric multipoles.
  • Magnetoelectric Classification of Skyrmions.
  •  The discovery of a finite-temperature critical point in the pressure-temperature phase diagram of SrCu2(BO3)2 .
  • The development of modeling and experimental proof of BEC of magnons in multiband condensate in YiG.
  • The development of Kapitza engineering for quantum paraelectrics.

A full list of publications (over 100 peer-reviewed papers) where these and other achievements and outcomes are reported is presented below.

13 July 2022
Romain Ganter tinkers with the finishing touches of the upgrade to Athos

Athos just got even better

An ambitious upgrade at the soft X-ray beamline of the free electron laser SwissFEL opens up new experimental capabilities.

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15 February 2022
Reiche, Aeppli and Gerber

Opening the door to X-ray quantum optics

The 'perfect' X-ray beam-splitter: Researchers at SwissFEL have an ingenious solution to produce coherent copies of pulses, facilitating a realm of new X-ray techniques.

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  • Calvi M, Liang X, Ferrari E, Alarcon A, Prat E, Reiche S, et al.
    Versatile modulators for laser-based FEL seeding at SwissFEL
    Journal of Synchrotron Radiation. 2023; 30: 276-283. https://doi.org/10.1107/S1600577522012073
    DORA PSI
  • D'Anna N, Ferreira Sanchez D, Matmon G, Bragg J, Constantinou PC, Stock TJZ, et al.
    Non-destructive X-Ray imaging of patterned Delta-Layer devices in silicon
    Advanced Electronic Materials. 2023; 2023: 202201212 (8 pp.). https://doi.org/10.1002/aelm.202201212
    DORA PSI
  • Prat E, Al Haddad A, Arrell C, Augustin S, Boll M, Bostedt C, et al.
    An X-ray free-electron laser with a highly configurable undulator and integrated chicanes for tailored pulse properties
    Nature Communications. 2023; 14: 5069 (11 pp.). https://doi.org/10.1038/s41467-023-40759-z
    DORA PSI
  • Ueda H, García-Fernández M, Agrestini S, Romao CP, van den Brink J, Spaldin NA, et al.
    Chiral phonons in quartz probed by X-rays
    Nature. 2023; 618: 946-950. https://doi.org/10.1038/s41586-023-06016-5
    DORA PSI
  • Wen Y, Giorgianni F, Ilyakov I, Quan B, Kovalev S, Wang C, et al.
    A universal route to efficient non-linear response via Thomson scattering in linear solids
    National Science Review. 2023; 10(7): nwad136 (10 pp.). https://doi.org/10.1093/nsr/nwad136
    DORA PSI
  • Beckert A, Grimm M, Hermans RI, Freeman JR, Linfield EH, Davies AG, et al.
    Precise determination of the low-energy electronuclear Hamiltonian of LiY1-xHoxF4
    Physical Review B. 2022; 106(11): 115119 (11 pp.). https://doi.org/10.1103/PhysRevB.106.115119
    DORA PSI
  • Finizio S, Bailey JB, Olsthoorn B, Raabe J
    Periodogram-based detection of unknown frequencies in time-resolved scanning transmission X-ray microscopy
    ACS Nano. 2022; 16(12): 21071-21078. https://doi.org/10.1021/acsnano.2c08874
    DORA PSI
  • Reiche S, Knopp G, Pedrini B, Prat E, Aeppli G, Gerber S
    A perfect X-ray beam splitter and its applications to time-domain interferometry and quantum optics exploiting free-electron lasers
    Proceedings of the National Academy of Sciences of the United States of America PNAS. 2022; 119(7): e2117906119 (5 pp.). https://doi.org/10.1073/pnas.2117906119
    DORA PSI
  • Aeppli G, Balatsky AV, Rønnow HM, Spaldin NA
    Hidden, entangled and resonating order
    Nature Reviews Materials. 2020; 5(7): 477-479. https://doi.org/10.1038/s41578-020-0207-z
    DORA PSI
  • Beckert A, Sigg H, Aeppli G
    Taking advantage of multiplet structure for lineshape analysis in Fourier space
    Optics Express. 2020; 28(17): 24937-24950. https://doi.org/10.1364/OE.395877
    DORA PSI
  • Dehn MH, Shenton JK, Holenstein S, Meier QN, Arseneau DJ, Cortie DL, et al.
    Observation of a charge-neutral muon-polaron complex in antiferromagnetic Cr2O3
    Physical Review X. 2020; 10(1): 011036 (18 pp.). https://doi.org/10.1103/PhysRevX.10.011036
    DORA PSI
  • Hermans RI, Seddon J, Shams H, Ponnampalam L, Seeds AJ, Aeppli G
    Ultra-high-resolution software-defined photonic terahertz spectroscopy
    Optica. 2020; 7(10): 1445-1455. https://doi.org/10.1364/OPTICA.397506
    DORA PSI
  • Krieger JA, Pertsova A, Giblin SR, Döbeli M, Prokscha T, Schneider CW, et al.
    Proximity-induced odd-frequency superconductivity in a topological insulator
    Physical Review Letters. 2020; 125(2): 026802 (6 pp.). https://doi.org/10.1103/PhysRevLett.125.026802
    DORA PSI
  • Müller M, Derlet PM, Mudry C, Aeppli G
    Testing of asymptomatic individuals for fast feedback-control of COVID-19 pandemic
    Physical Biology. 2020; 17(6): 065007 (20 pp.). https://doi.org/10.1088/1478-3975/aba6d0
    DORA PSI

Bhowal, Sayantika; Spaldin, Nicola A.
Polar Metals: Principles and Prospects
Annual Review of Materials Research. 2023. 53: 53-79. https://doi.org/10.1146/annurev-matsci-080921-105501

Frey, Ramon; Grosso, Bastien F.; Fandré, Pascal; et al.
Accelerated search for new ferroelectric materials
Physical Review Research. 2023. 5(2): 023122. https://doi.org/10.1103/physrevresearch.5.023122

Vogel, Alexander; Ruiz Caridad, Alicia; Nordlander, Johanna; et al.
Origin of the Critical Thickness in Improper Ferroelectric Thin Films 
ACS Applied Materials & Interfaces. 2023. 15(14): 18482 - 18492. https://doi.org/10.3929/ethz-b-000606258

Pásztorová, Jana; Mansouri Tehrani, Aria; Živković, Ivica; et al.
Experimental and theoretical thermodynamic studies in Ba2MgReO6—the ground state in the context of Jahn-Teller effect
Journal of Physics: Condensed Matter. 2023. 35(24): 245603. https://doi.org/10.1088/1361-648X/acc62a

Weber, Sophie F.; Spaldin, Nicola A.
Characterizing and Overcoming Surface Paramagnetism in Magnetoelectric Antiferromagnets
 Physical Review Letters. 2023. 130(14): 146701. https://doi.org/10.1103/PhysRevLett.130.146701

Ueda, Hiroki; García-Fernández, Mirian; Agrestini, Stefano; et al.
Chiral phonons in quartz probed by X-rays
Nature. 2023. 618(7967): 946 - 950. https://doi.org/10.1038/s41586-023-06016-5
Mansouri Tehrani, Aria; Soh, Jian-Rui; Pásztorová, Jana; et al.
Charge multipole correlations and order in Cs2TaCl6 
Physical Review Research. 2023. 5(1): L012010. https://doi.org/10.1103/PhysRevResearch.5.L012010

Pásztorová, Jana; Mansouri Tehrani, Aria; Živković, Ivica; et al.
Experimental and theoretical thermodynamic studies in Ba2MgReO6—the ground state in the context of Jahn-Teller effect
Journal of Physics: Condensed Matter. 2023;  35 (24): 245603. https://doi.org/10.1088/1361-648X/acc62a

Esswein, Tobias; Spaldin, Nicola A.
Ferroelectric, quantum paraelectric, or paraelectric? Calculating the evolution from BaTiO3 to SrTiO3 to KTaO3 using a single-particle quantum mechanical description of the ions 
Physical Review Research. 2022; 4 (3): 033020. https://doi.org/10.1103/PhysRevResearch.4.033020

Tosic, Tara Niamh; Meier, Quintin N.; Spaldin, Nicola A.
Influence of the triangular Mn-O breathing mode on magnetic ordering in multiferroic hexagonal manganites Physical Review Research. 2022 4(3): 033204. https://doi.org/10.3929/ethz-b-000573854

Bhowal, Sayantika; Spaldin, Nicola A.
Magnetoelectric Classification of Skyrmions 
Physical Review Letters. 2022. 128(22): 227204. https://doi.org/10.1103/PhysRevLett.128.227204

Grosso, Bastien Francesco; Spaldin, Nicola A.; Mansouri Tehrani, Aria.
Physics-Guided Descriptors for Prediction of Structural Polymorphs
The Journal of Physical Chemistry Letters. 2022. 13(31): 7342 - 7349. https://doi.org/10.1021/acs.jpclett.2c01876

Urru, Andrea; Spaldin, Nicola A.
Magnetic octupole tensor decomposition and second-order magnetoelectric effect 
Annals of Physics. 2022. 447: 168964.https://doi.org/10.1016/j.aop.2022.168964

Kim, Donghoon; Efe, Ipek; Torlakcik, Harun; et al.
Magnetoelectric Effect in Hydrogen Harvesting: Magnetic Field as a Trigger of Catalytic Reactions 
Advanced Materials. 2022; 34 (19): 2110612. https://doi.org/10.1002/adma.202110612

Bhowal, Sayantika; Collins, Stephen P.; Spaldin, Nicola A.
Hidden k -Space Magnetoelectric Multipoles in Nonmagnetic Ferroelectrics 
Physical Review Letters. 2022; 128 (11): 116402.https://doi.org/10.1103/PhysRevLett.128.116402

Meier, Quintin N.; Hickox-Young, Daniel; Laurita, Geneva; et al.
Leggett Modes Accompanying Crystallographic Phase Transitions 
Physical Review X. 2022; 12 (1): 011024. https://doi.org/10.1103/PhysRevX.12.011024

Gattinoni, Chiara; Spaldin, Nicola A.
Prediction of a strong polarizing field in thin film paraelectrics 
Physical Review Research. 2022; 4 (3): L032020. https://doi.org/10.1103/PhysRevResearch.4.L032020

Bhowal, Sayantika; O'Neill, Daniel; Fechner, Michael; et al.
Anti-symmetric Compton scattering in LiNiPO4: Towards a direct probe of the magneto-electric multipole moment 
Open Research Europe. 2021; 1: 132. https://doi.org/10.12688/openreseurope.13863.1

Mansouri Tehrani, Aria; Spaldin, Nicola A.
Untangling the structural, magnetic dipole, and charge multipolar orders in Ba2MgReO6 
Physical Review Materials. 2021; 5 (10): 104410. https://doi.org/10.1103/physrevmaterials.5.104410

Bhowal, Sayantika; Spaldin, Nicola A.
Revealing hidden magnetoelectric multipoles using Compton scattering 
Physical Review Research. 2021. 3(3): 033185. https://doi.org/10.1103/physrevresearch.3.033185

Catena, Riccardo; Emken, Timon; Matas, Marek; et al.
Crystal responses to general dark matter-electron interactions 
Physical Review Research. 2021; 3(3): 033149. https://doi.org/10.1103/physrevresearch.3.033149

Michel, Veronica F.; Esswein, Tobias; Spaldin, Nicola A.
Interplay between ferroelectricity and metallicity in BaTiO3 
Journal of Materials Chemistry C. 2021; 9(27): 8640 - 8649. https://doi.org/10.1039/d1tc01868j

Giraldo Castaño, Leidy Marcela; Meier, Quintin N.; Bortis, Amadé; et al.
Magnetoelectric coupling of domains, domain walls and vortices in a multiferroic with independent magnetic and electric order 
Nature Communications. 2021; 12(1): 3093. https://doi.org/10.1038/s41467-021-22587-1

Spaldin, Nicola A.; Efe, Ipek; Rossell, Marta D.; et al.
Layer and spontaneous polarizations in perovskite oxides and their interplay in multiferroic bismuth ferrite 
The Journal of Chemical Physics. 2021; 154 (15): 154702. https://doi.org/10.1063/5.0046061

Efe, Ipek; Spaldin, Nicola A.; Gattinoni, Chiara
On the happiness of ferroelectric surfaces and its role in water dissociation: The example of bismuth ferrite 
The Journal of Chemical Physics. 2021; 154 (2): 024702. https://doi.org/10.1063/5.0033897

Dehn, Martin H.; Shenton, J. Kane; Arseneau, Donald J.; et al.
Local Electronic Structure and Dynamics of Muon-Polaron Complexes in Fe2 O3 
Physical Review Letters. 2021; 126 (3): 037202. https://doi.org/10.1103/PhysRevLett.126.037202

Spaldin, Nicola
Analogy between the Magnetic Dipole Moment at the Surface of a Magnetoelectric and the Electric Charge at the Surface of a Ferroelectric 
Žurnal Èksperimental'noj i Teoretičeskoj Fiziki. 2021; 159 (4). https://doi.org/10.1134/S1063776121040208

Juraschek, Dominik M.; Meier, Quintin N.; Narang, Prineha
Parametric Excitation of an Optically Silent Goldstone-Like Phonon Mode 
Physical Review Letters. 2020; 124 (11): 117401. https://doi.org/10.1103/PhysRevLett.124.117401

Spaldin, Nicola
Multiferroics beyond electric-field control of magnetism
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 2020; 476 (2233): 20190542. https://doi.org/10.1098/rspa.2019.0542

Catena, Riccardo; Emken, Timon; Spaldin, Nicola; et al.
Atomic responses to general dark matter-electron interactions 
Physical Review Research. 2020; 2 (3): 033195. https://doi.org/10.1103/physrevresearch.2.033195

Juraschek, Dominik M.; Narang, Prineha; Spaldin, Nicola
Phono-magnetic analogs to opto-magnetic effects 
Physical Review Research. 2020; 2 (4): 043035. https://doi.org/10.1103/PhysRevResearch.2.043035

Dehn, Martin H.; Shenton, John K.; Holenstein, Stefan; et al.
Observation of a Charge-Neutral Muon-Polaron Complex in Antiferromagnetic Cr2O3 
Physical Review X. 2020; 10 (1): 011036. https://doi.org/10.1103/PhysRevX.10.011036

Thöle, Florian; Keliri, Andriani; Spaldin, Nicola
Concepts from the linear magnetoelectric effect that might be useful for antiferromagnetic spintronics 
Journal of Applied Physics. 2020; 127 (21): 213905. https://doi.org/10.1063/5.0006071

Meier, Quintin N.; Stucky, Adrien; Teyssier, Jeremie; et al.
Manifestation of structural Higgs and Goldstone modes in the hexagonal manganites 
Physical Review. 2020; 102 (1): 014102. https://doi.org/10.1103/PhysRevB.102.014102

Ellen Fogh, Bastian Klemke, Alexandre Pages, Jiying Li, David Vaknin, Henrik M. Rønnow, Niels B. Christensen, Rasmus Toft-Petersen.
The magnetoelectric effect in LiFePO – revisited
Physica B Condensed Matter Volume. 2023. 648: 414380. https://doi.org/10.1016/j.physb.2022.414380.

Ivica Živković, Ravi Yadav, Jian-Rui Soh, ChangJiang Yi, YouGuo Shi, Oleg V. Yazyev, and Henrik M. Rønnow.
Unraveling the origin of the peculiar transition in the magnetically ordered phase of the Weyl semimetal Co3Sn2S2.
Phys. Rev. B. 2022. 106: L180403. https://doi.org/10.1103/PhysRevB.106.L180403.

J. Larrea Jimenez; S. P. G. Crone; E. Fogh; M. E. Zayed; R. Lortz et al. 
A quantum magnetic analogue to the critical point of water
Nature. 2021;  592: 370–375. https://doi.org/10.1038/s41586-021-03411-8

Ping Huang, Marco Cantoni,   Arnaud Magrez,   Fabrizio Carbonec  and  Henrik M. Rønnow.
Electric field writing and erasing of skyrmions in magnetoelectric Cu2OSeO3 with an ultralow energy barrier
Nanoscale, 2022,14, 16655-16660. https://doi.org/10.1039/D2NR04399H.

Luc Testa, Peter Babkevich, Yasuyuki Kato, Kenta Kimura, Virgile Favre, Jose A. Rodriguez-Rivera, Jacques Ollivier, Stéphane Raymond, Tsuyoshi Kimura, Yukitoshi Motome, Bruce Normand, and Henrik M. Rønnow.
Spin dynamics in the square-lattice cupola system Ba(TiO)Cu4(PO4)4
Phys. Rev. B. 2022. 105: 214406 . https://doi.org/10.1103/PhysRevB.105.214406.

E. Fogh, O. Mustonen, P.Babkevich, V. M. Katukuri, H.C. Walker et al.
Randomness and frustration in a S=1/2 square-lattice Heisenberg antiferromagnet
Physical Review B. 2022; 105: 184410. https://doi.org/10.1103/PhysRevB.105.184410

H. Papi; V. Y. Favre; H. Ahmadvand; M. Alaei; M. Khondabi et al. 
Magnetic and structural properties of Ni-substituted magnetoelectric Co4Nb2O9
Physical Review B. 2019; 100:134408. https://doi.org/10.1103/PhysRevB.100.134408

P. Huang; T. Schonenberger; M. Cantoni; L. Heinen; A. Magrez et al. 
Melting of a skyrmion lattice to a skyrmion liquid via a hexatic phase
Nature Nanotechnology. 2020;  15: 761–767. https://doi.org/10.1038/s41565-020-0716-3

L. Testa; V. Surija; K. Prsa; P. Steffens; M. Boehm et al. 
Triplons, magnons, and spinons in a single quantum spin system: SeCuO3
Physical Review B. 2021; 103: L020409. https://doi.org/10.1103/PhysRevB.103.L020409

R. Matthias Geilhufe
Dynamic electron-phonon and spin-phonon interactions due to inertia
Physical Review Research. 2022; 4: L012004. https://doi.org/10.1103/PhysRevResearch.4.L012004

Alexander Khaetskii, Vladimir Juričič, Alexander V Balatsky
Thermal magnetic fluctuations of a ferroelectric quantum critical point
Journal of Physics: Condensed Matter. 2021; 33/4: 04LT. https://doi.org/10.1088/1361-648X/abbb0f

R. Matthias Geilhufe
Quantum Buckling in Metal–Organic Framework Materials
Nano Letters. 2021; 21, 24: 10341–10345.  https://doi.org/10.1021/acs.nanolett.1c03579

Geilhufe, R.M., Olsthoorn, B. & Balatsky, A.V.
Shifting computational boundaries for complex organic materials.
Nature Physics. 2021; 17: 152–154 . https://doi.org/10.1038/s41567-020-01135-6

Gayanath W. Fernando; R. Matthias Geilhufe; Adil-Gerai Kussow; W. Wasanthi P. De Silva
Driven emergent phases in small interacting condensed-matter systems
Europhysics Letters. 2021; 134: 37004. https://doi.org/10.1209/0295-5075/134/37004

Long Liang, P. O. Sukhachov, and A. V. Balatsky

Axial Magnetoelectric Effect in Dirac Semimetals.
Physical Review Letters. 2021; 126: 247202. https://doi.org/10.1103/PhysRevLett.126.247202

R. Matthias Geilhufe; Vladimir Juricic; Stefano Bonetti; Jian-Xin Zhu; Alexander V. Balatsky
Dynamically induced magnetism in KTaO 3
Physical Review Research. 2021;  3: L022011. https://doi.org/10.1103/PhysRevResearch.3.L022011

Henrik Schou Røising; Benjo Fraser; Sinéad M. Griffin; Sumanta Bandyopadhyay; Aditi Mahabir; et al.
Axion-matter coupling in multiferroics
Physical Review Research. 2021; 3: 033236. https://doi.org/10.1103/PhysRevResearch.3.033236

Jonas A. Krieger, Anna Pertsova, Sean R. Giblin, Max Döbeli, Thomas Prokscha, et al.
Proximity-Induced Odd-Frequency Superconductivity in a Topological Insulator
Physical Review Letters. 2020; 125: 026802. https://doi.org/10.1103/PhysRevLett.125.026802

R. Matthias Geilhufe, Felix Kahlhoefer, and Martin Wolfgang Winkler
Dirac materials for sub-MeV dark matter detection: New targets and improved formalism
Physical Review D. 2020; 101: 055005. https://doi.org/10.1103/PhysRevD.101.055005

Dushko Kuzmanovski, Rubén Seoane Souto, and Alexander V. Balatsky
Odd-frequency superconductivity near a magnetic impurity in a conventional superconductor
Physical Review  B. 2020; 101: 094505. https://doi.org/10.1103/PhysRevB.101.094505

Rubén Seoane Souto, Dushko Kuzmanovski, and Alexander V. Balatsky
Signatures of odd-frequency pairing in the Josephson junction current noise
Physical Review Research. 2020; 2: 043193. https://doi.org/10.1103/PhysRevResearch.2.043193

P. O. Sukhachov and H. Rostam
Acoustogalvanic Effect in Dirac and Weyl Semimetals
Physical Review Letters. 2020; 124: 126602. https://doi.org/10.1103/PhysRevLett.124.126602

Olsthoorn, Bart; Balatsky, Alexander V.
Mass fluctuations and absorption rates in dark-matter sensors based on Dirac materials
Physical Review B. 2020; 101: 045120. https://doi.org/10.1103/PhysRevB.101.045120

Bart Olsthoorn; Johan Hellsvik; Alexander V. Balatsky
Finding hidden order in spin models with persistent homology
Physical Review Research.2020; 2: 043308. https://doi.org/10.1103/PhysRevResearch.2.043308

Sumanta Bandyopadhyay; Gerardo Ortiz; Zohar Nussinov; Alexander Seidel
Local Two-Body Parent Hamiltonians for the Entire Jain Sequence.
Physical Review Letters. 2020; 124: 196803. https://doi.org/10.1103/PhysRevLett.124.196803

P. O. Sukhachov and A. V. Balatsky
Spectroscopic and optical response of odd-frequency superconductors
Physical Review  B. 2019; 100: 134516. https://doi.org/10.1103/PhysRevB.100.134516

Jacob Linder and Alexander V. Balatsky
Odd-frequency superconductivity
Reviews of Modern Physics. 2019; 91: 045005. https://doi.org/10.1103/RevModPhys.91.045005