Petr Čermák

Scientific researcher, doctor of physics

Hello! I´m Petr and I do science.
I have MaMBA 🐍.
I work at low temperature magnetic laboratory MGML in Prague .

Featured publications:

Petr Čermák et al., PNAS 116 (2019) 6695-6700

B.-Q. Liu, P. Čermák et al., Phys. Rev. B 98 (2018) 174306

Education and career.

  • 2005-2010

    Bachelor + Master study, Charles University, Prague, CZ

    I studied solid-state physics and materials research and specialized in specific heat analysis. I wrote bachelor thesis Analysis of magnetic contribution to the specific heat of compounds Ce1-xYxPdAl (in czech, download) and master thesis Magnetic properties of Ce compounds studied by specific heat (download), both under the supervision of Prof. Dr. Pavel Javorský. I achieved Bachelor’s and Master's degree in physics (both Summa cum Laude).

  • 2010-2014

    Doctor study, Charles University, Prague, CZ

    I started my PhD in Prague, prepared the samples and measured bulk properties of them with my supervisor Prof. Dr. Pavel Javorský. For the last year I moved to ILL, Grenoble where I finished magnetic structure determination and worked on Monte Carlo neutron simulations and Triple Axis spectrometer development (ThALES) under supervision of Martin Böhm. I was also part of the team coding Esmeralda suite for LAUE treatment lead by Juan-Rodrigez Carvajal.

  • 2013-2018

    Instrument Responsible at TAS PANDA

    I was employed by Forschungszentrum Jülich GmBH outstation at MLZ, Garching as a 2nd Instrument Responsible at Tripple Axis Spectrometer PANDA in the team of Dr. Astrid Schneidewind. I learned about hardware developement, advanced data analysis and maintenance of the large scientific facility. I began the cooperation with the group E21/51 of Prof. Dr. Christian Pfleiderer and specialized in crystal field-phonon coupling.

  • 2018-now

    Scientist at MGML

    Currently I work in Prague at Material Growth & Mesurement Laboratory at Karlov, employed by Charles University. I have a small group and we do science.

Research.

Neutron scattering

I am a big fan of neutrons and I use them to explore matter. I worked 5 years as instrument responsible of Three Axis Spectrometer PANDA in second largest scientific reactor in Europe: MLZ facility, Garching, Germany.

I really love neutrons and you should too!
They are unique because their mass is comparable with atoms and their energy is comparable with interatomic distances. In addition they have no charge so they penetrate deep into materials. And last but not least: they have spin to interact with magnetic moments!

I specialize in diffraction and three axis spectroscopy.

Magnetoelastic coupling

The interplay between magnetic moments and lattice vibrations is a general and known condensed matter property. I am interrested on rare earth metals, where the magnetic behaviour is strongly influenced by the local point-symmetry of the surrounding.

Crystalline electric field effect is usually static in momentum; except the CEF transitions between neighboring ions couple and create magnetic excitons. If this coupling is phonon-mediated we speak about magnetoelastic coupling. For very strong MEL the creation of an additional magnetic vibornic bound state is possible, and in the case of weaker coupling one can observe mixed quadrupole-phonon excitations visible as an anticrossing in the inelastic scattering. I look for coumpound exhibiting these phenomenas and try to evaluate measured results. Because crystal field is often not studied dynamically I am developing software to analyze it. Check out CrysFiPy project site!

Cooperation

I am a member of several project-related teams:

  • Nonequivalent Kondo Sites
  • The Growth Kinetics of Multiferroics
  • Multi-Component Correlations
  • Quantum Kagome Magnets
Kondo lattices with nonequivalent sites

The existence of the nonequivalent crystallographic Kondo sites lead to the formation of two sublattices with largely different Kondo temperatures. We expect such systems to show better tunability towards various kinds of quantum phase transitions than single-site Kondo systems, and to form novel phases. The project is funded as a project GAČR 18-23606S.

An in-situ study of the Growth Kinetics of Pulsed Laser Deposition of Multiferroic Complex Oxides

The goal of the project is to gain fundamental understanding in the growth of complex oxides by pulsed-laser deposition (PLD) enabling to optimize the growth parameters for fabricating oxide systems with the best multiferroic performance. The project is international German-Czech cooperation funded under GAČR 19-10799J.

Multi-Component Electronic Correlations in Non-Centrosymmetric f-Electron Compounds

In metallic f-electron compounds the effects of electronic correlations are exceptionally pronounced, driving conventional and unconventional forms of spin and charge order. We are developing a detailed phenomenological account of the nature of electronic correlations in carefully selected non-centrosymmetric f-electron compounds, combining the preparation of high quality single-crystals, bulk and transport measurements under extreme conditions, comprehensive neutron scattering studies and measurements of quantum oscillations. This is international German-Czech project DFG WI3320-3 / GAČR 17-04925J.

Investigation of quantum kagome magnets by ordered substitution of fluoride pyrochlores

This project is dedicated to the synthesis and study of the magnetic and electronic properties of new quantum (S=1/2) kagome antiferromagnets utilising the ordered substitution of a pyrochlore lattice. The project is funded as a project GAČR 19-21575Y.

Data evaluation

I am Jupyter and open source maximalist. Scientists should publish not only manuscripts, but also source data and also (!) scripts to evaluate them. I help with suitable software developement and specialized courses.

Check my projects:

- TAS workshop - Ufit - Laue Suite

Reviewer

Peer-review process is crucial part of scientific evaluation. I am a member of ISIS Facility Access Panels (FAP) 4 - Excitations and I do peer-review for several journals. I am a big fan of opened peer-review and SciPost journal.

Peer-review process is crucial part of scientific evaluation and it is important to participate and judge scientific works of other collegues. I am a member of ISIS Facility Access Panels (FAP) 4 - Excitations. We meet twice a year and rank proposals for ISIS Neutron and Muon Source on a scale from 10 to 1. ISIS Facility is world-leading centre for research in the physical and life sciences.

In addition I do peer-review for several journals, like Intermetallics or Journal of Magnetism and Magnetic Materials. I am a big fan of opened peer-review and SciPost journal

More info:

My Publons profile ISIS FAP website SciPost journal

Publications.

Evidence for singular-phonon-induced nematic superconductivity in Sr0.1Bi2Se3

Nat. Commun. 10, 2802 (2019)

In this work, by performing inelastic neutron scattering measurements on a superconducting single crystal of Sr0.1Bi2Se3, a prime candidate for realizing topological superconductivity, we find that there exist highly anisotropic phonons, with the linewidths of the acoustic phonons increasing substantially at long wavelengths, but only for those along the [001] direction. This observation indicates a large and singular electron-phonon coupling at small momenta, which we propose to give rise to the exotic p-wave nematic superconducting pairing.

Read the article (chinese)

Abundance of magneto-elastic functionalities

PNAS 2019 116 (14) 6695-6700

An international team from the Forschungszentrum Jülich and the Technical University of Munich led by Dr. Petr Cermak (now Charles University of Prague) shed unexpected new light on the abundance of magnetoelastic interactions in solids. Using inelastic neutron scattering on a single crystal of the rare-earth intermetallic compound CeAuAl3 revealed, that electron-phonon interaction can lead to creation of the new states in the matter, even in the case of small and hard to measure interactions.

Read the article
Another article at MLZ

Neutrons reveal that spin glass can mimic quantum spin liquid

Phys. Rev. Lett. 120, 087201 (2018)

Quantum spin liquids represent a novel state of matter in which the spins do not arrange themselves in an ordered pattern as they do in a conventional magnet. This state features spins with long-range entanglements and fractional excitations, and thus can find applications in quantum computation and communication.
Current work is result of several chalenging experiments on PANDA spectrometer.

Read the article

Triple Axis Resolution Workshop at MLZ Garching

Neutron News, 28(3), p. 10 (2017)

On April 3rd and 4th, 2017 the quantum phenomena group of the MLZ organised a two-day workshop on software for calculating the resolution function of a three axes spectrometer and convoluting the data with theoretical models.
I prepared the programme of the workshop and also hands-on session with advanced analysis of TAS data.

Read the article, page 18

Neutron-scattering experiments explore origins of high-temp superconductivity

Nature Communications 7, 12774 (2016)

New findings from researchers at Rice University, the University of Illinois at Chicago and the University of California at San Diego (UCSD) suggest that condensed-matter physicists need to rethink how magnetic fluctuations arise in both unconventional and high-temperature superconductors.
Details about resonance dispersion are determined on PANDA spectrometer.

Read the article
List of all publications

Teaching.

Contact.

[email protected] +420 95155 1653
  • Department of Condensed Matter Physics
  • Charles University, Fac. of Math. and Phys
  • Ke Karlovu 5
  • 121 16 Prague 2