In order to gain information about the properties of the above-cited materials we primarily use Raman scattering and X-ray Scattering. Raman scattering has been widely used to study lattice, magnetic and electronic excitations in solids. The use of lasers light in the visible range allows to reach high energy resolution (below 1 meV), whereas the selection of incoming and outgoing polarizations of the light allows to disentangle contributions from different irreducible representations of the space group of the system. Various excitation lines are available in our laboratories, so that we are also able to explore possible resonance effects. Our group currently operates 2 state-of-the-art high-resolution Raman spectrometers: a single-grating Jobin Yvon LabRAM HR800 and a Jobin Yvon T64000 triple-grating spectrometer. The LabRAM setup is capable of measuring the excitation spectra from very thin films by using a combination of motorized objective lens with short depth-of-focus and a precisely calibrated confocal hole along the scattering path.
Due to the small momentum carried by visible light, the information obtained from Raman scattering experiments is essentially limited to the center of the Brillouin zone. Thus, in order to gain insights about the dispersion of the observed excitations, it is necessary to complement the Raman measurements with scattering probes providing a non-negligible momentum transfer, such as x-rays. To this aim, we take advantage of the latest technical improvements in synchrotron radiation facilities carrying out non-resonant and Resonant Inelastic X-ray Scattering (RIXS) experiments.
In particular RIXS, thanks to its element selectivity, is a powerful tool to measure collective excitations of strongly correlated systems and it has allowed a remarkable series of scientic achievements over the last few years, including, for example, the direct observation of both high-energy collective spin excitations and charge density waves in high-Tc
superconduting cuprates. In RIXS an incoming photon with energy tuned to an absorption edge of the material hits the sample and excites the system. One observes then the radiative decay of the excited state. The energy of the emitted photons in a given direction is accurately measured with a spectrometer, to obtain the energy and momentum transferred in the scattering event from the photon to the sample. RIXS is thus capable of mapping out dispersive excitations in a wide region of the reciprocal space. Crucially, the high sensitivity of RIXS, due to the resonant nature of the scattering process, allows also the study of ultrathin layers of material (down to a few unit cells), overcoming the technical limitations of alternative techniques like inelastic neutron scattering, which requires instead more massive samples.
Finally, we carry out Raman and x-ray scattering measurements also as a function of uniaxial strain by means of a device, based on piezo-electrics and developed at the MPI in Dresden, that we integrated into the setups that we use in-house and at the synchrotron.Selected Publications"Resonant inelastic x-ray scattering from electronic excitations in α − RuCl3 nanolayers"
Zichen Yang, Lichen Wang, Dong Zhao, Mingdi Luo, Sourav Laha, Achim Güth, Takashi Taniguchi, Kenji Watanabe, Bettina V. Lotsch, Jurgen H. Smet, Matteo Minola, Hlynur Gretarsson, and Bernhard KeimerPhys. Rev. B 108, L041406 (2023)
"Normal-state charge transport in YBa2Cu3O6.67 under uniaxial stress"
S. Nakata, P. Yang, M. E. Barber, K. Ishida, H.-H. Kim, T. Loew, M. Le Tacon, A. P. Mackenzie, M. Minola, C. W. Hicks, B. Keimernpj Quantum Materials 7, 118 (2022) "Dependence of Tc of YBa2Cu3O6.67 on in-plane uniaxial stress"
Mark E. Barber, Hun-ho Kim, Toshinao Loew, Matthieu Le Tacon, Matteo Minola, Marcin Konczykowski, Bernhard Keimer, Andrew P. Mackenzie, and Clifford W. HicksPhys. Rev. B 106, 184516 (2022) "Giant stress response of terahertz magnons in a spin-orbit Mott insulator"
Hun-Ho Kim, Kentaro Ueda, Suguru Nakata, Peter Wochner, Andrew Mackenzie, Clifford Hicks, Giniyat Khaliullin, Huimei Liu, Bernhard Keimer & Matteo MinolaNature Communications 13, 6674 (2022) "Paramagnons and high-temperature superconductivity in a model family of cuprates"
Lichen Wang, Guanhong He, Zichen Yang, Mirian Garcia-Fernandez, Abhishek Nag, Kejin Zhou, Matteo Minola, Matthieu Le Tacon, Bernhard Keimer, Yingying Peng, Yuan LiNature Communications 13, 3163 (2022) "Dynamic electron correlations with charge order wavelength along all directions in the copper oxide plane"
F. Boschini, M. Minola, R. Sutarto, E. Schierle, M. Bluschke, S. Das, Y. Yang, M. Michiardi, Y. C. Shao, X. Feng, S. Ono, R. D. Zhong, J. A. Schneeloch, G.D. Gu, E. Weschke, F. He, Y. D. Chuang, B. Keimer, A. Damascelli, A. Frano and E. H. da Silva NetoNature Communications 12, 597 (2021)"Charge Density Waves in YBa2Cu3O6.67 Probed by Resonant X-Ray Scattering under Uniaxial Compression"
H.-H. Kim, E. Lefrançois, K. Kummer, R. Fumagalli, N. B. Brookes, D. Betto, S. Nakata, M. Tortora, J. Porras, T. Loew, M. E. Barber, L. Braicovich, A. P. Mackenzie, C. W. Hicks, B. Keimer, M. Minola, and M. Le TaconPhys. Rev. Lett 126, 037002 (2021) "Imprint of charge and oxygen orders on Dy ions in DyBa2Cu3O6+x thin films probed by resonant x-ray scattering"
Davide Betto, Martin Bluschke, Daniel Putzky, Enrico Schierle, Andrea Amorese, Katrin Fürsich, Santiago Blanco-Canosa, Georg Christiani, Gennady Logvenov, Bernhard Keimer, Matteo MinolaPhys. Rev. B 102, 195149 (2020) "Backfolded acoustic phonons as ultrasonic probes in metal-oxide superlattices"
F. Lyzwa, A. Chan, J. Khmaladze, K. Fürsich, B. Keimer, C. Bernhard, M. Minola, and B. P. P. MallettPhys. Rev. Materials 4, 043606 (2020) "Structural, Electronic and Magnetic Properties of a Few Nanometer-Thick Superconducting NdBa2Cu3O7 Films"
Marco Moretti Sala, Marco Salluzzo, Matteo Minola, Gabriella Maria De Luca, Greta Dellea, Vesna Srot, Yi Wang, Peter A. van Aken, Matthieu Le Tacon, Bernhard Keimer, Claudia Dallera, Lucio Braicovich, Giacomo Ghiringhelli Nanomaterials, 10 (4), 817 (2020) "Raman scattering from current-stabilized nonequilibrium phases in Ca2RuO4"
K. Fürsich, J. Bertinshaw, P. Butler, M. Krautloher, M. Minola, and B. KeimerPhys. Rev. B 100, 081101(R) (2019) "Polarization-resolved Cu L3-edge resonant inelastic x-ray scattering of orbital and spin excitations in NdBa2Cu3O7−δ"
R. Fumagalli, L. Braicovich, M. Minola, Y. Y. Peng, K. Kummer, D. Betto, M. Rossi, E. Lefrançois, C. Morawe, M. Salluzzo, H. Suzuki, F. Yakhou, M. Le Tacon, B. Keimer, N. B. Brookes, M. Moretti Sala, and G. Ghiringhelli Phys. Rev. B 99, 134517 (2019) - Editor's Suggestion"Resonant inelastic x-ray scattering study of bond order and spin excitations in nickelate thin-film structures"
K. Fürsich, Y. Lu, D. Betto, M. Bluschke, J. Porras, E. Schierle, R. Ortiz, H. Suzuki, G. Cristiani, G. Logvenov, N. B. Brookes, M. W. Haverkort, M. Le Tacon, E. Benckiser, M. Minola, and B. Keimer Phys. Rev. B 99, 165124 (2019) - Editor's Suggestion"Probing the energy gap of high-temperature cuprate superconductors by resonant inelastic x-ray scattering"
H. Suzuki, M. Minola, Yi Lu, Yingying Peng, R. Fumagalli, E. Lefrançois, T. Loew, J. Porras, K. Kummer, D. Betto, Shigeyuki Ishida, Hiroshi Eisaki, Cheng Hu, Xingjiang Zhou, M. W. Haverkort, N. B. Brookes, L. Braicovich, G. Ghiringhelli, M. Le Tacon and B. Keimer npj Quantum Materials 3, 65 (2018) "Uniaxial pressure control of competing orders in a high-temperature superconductor"
H.-H. Kim, S. M. Souliou, M. E. Barber, E. Lefrançois, M. Minola, M. Tortora, R. Heid, N. Nandi, R. A. Borzi, G. Garbarino, A. Bosak, J. Porras, T. Loew, M. König, P. M. Moll, A. P. Mackenzie, B. Keimer, C. W. Hicks, M. Le TaconScience, 362, 6418, 1040-1044 (2018)"Coupling between dynamic magnetic and charge-order correlations in the cuprate superconductor Nd2−xCexCuO4"
E. H. da Silva Neto, M. Minola, B. Yu, W. Tabis, M. Bluschke, D. Unruh, H. Suzuki, Y. Li, G. Yu, D. Betto, K. Kummer, F. Yakhou, N. B. Brookes, M. Le Tacon, M. Greven, B. Keimer, and A. DamascelliPhys. Rev. B 98, 161114 (2018) "Stabilization of three-dimensional charge order in YBa2 Cu3O6+x via epitaxial growth"
M. Bluschke, A. Frano, E. Schierle, D. Putzky, F. Ghorbani, R. Ortiz, H. Suzuki, G. Christiani, G. Logvenov, E. Weschke, R.J. Birgeneau, E.H. da Silva Neto, M. Minola, S. Blanco-Canosa and B. KeimerNature Communications 9, 2978 (2018)"Site-Selective Probe of Magnetic Excitations in Rare-Earth Nickelates Using Resonant Inelastic X-ray Scattering"
Y. Lu, D. Betto, K. Fürsich, H. Suzuki, H.-H. Kim, G. Cristiani, G. Logvenov, N. B. Brookes, E. Benckiser, M. W. Haverkort, G. Khaliullin, M. Le Tacon, M. Minola, and B. KeimerPhys. Rev. X 8, 031014 (2018) "Selective formation of apical oxygen vacancies in La2−xSrxCuO4"
Gideok Kim, Georg Christiani, Gennady Logvenov, Sungkyun Choi, Hun-Ho Kim, M. Minola, and B. KeimerPhys.Rev. Materials 1, 054801 (2017)"Crossover from Collective to Incoherent Spin Excitations in Superconducting Cuprates Probed by Detuned Resonant Inelastic X-Ray Scattering"
M. Minola, Y. Lu, Y. Y. Peng, G. Dellea, H. Gretarsson, M. W. Haverkort, Y. Ding, X. Sun, X. J. Zhou, D. C. Peets, L. Chauviere, P. Dosanjh, D. A. Bonn, R. Liang, A. Damascelli, M. Dantz, X. Lu, T. Schmitt, L. Braicovich, G. Ghiringhelli, B. Keimer, and M. Le TaconPhys. Rev. Lett. 119, 097001 (2017)"Collective Nature of Spin Excitations in Superconducting Cuprates Probed by Resonant Inelastic X-Ray Scattering"
M. Minola, G. Dellea, H. Gretarsson, Y. Y. Peng, Y. Lu, J. Porras, T. Loew, F. Yakhou, N. B. Brookes, Y. B. Huang, J. Pelliciari, T. Schmitt, G. Ghiringhelli, B. Keimer, L. Braicovich, M. Le TaconPhys. Rev. Lett. 114, 217003, (2015)"Tunable Charge and Spin Order in PrNiO3 Thin Films and Superlattices"
M. Hepting, M. Minola, A. Frano, G. Cristiani, G. Logvenov, E. Schierle, M. Wu, M. Bluschke, E. Weschke, H.-U. Habermeier, E. Benckiser, M. Le Tacon, and B. KeimerPhys. Rev. Lett. 113, 227206 (2014)"Long-range incommensurate charge fluctuations in (Y,Nd)Ba2Cu3O6+x"
G. Ghiringhelli, M. Le Tacon, M. Minola, S. Blanco-Canosa, C. Mazzoli, N. B. Brookes, G. M. De Luca, A. Frañó, D. G. Hawthorn, F. He, T. Loew, M. Moretti Sala, D. C. Peets, M. Salluzzo, E. Schierle, R. Sutarto, G. A. Sawatzky, E. Weschke, B. Keimer, L. Braicovich.Science 337, 821 (2012)