November 22, 2023
PSI Villigen
Europe/Zurich timezone

Probing material properties with neutrons under pressure

Nov 22, 2023, 10:30 AM
Auditorium (WHGA) (PSI Villigen)

Auditorium (WHGA)

PSI Villigen


Ellen Fogh (EPFL - EPF Lausanne)


Quantum magnets are physical realisations of many-body quantum systems which may host interesting phenomena such as entangled states or spin-nematic states and quantum phase transitions. There exists a number of experimental knobs for controlling the state of such system: Temperature, magnetic field, chemical doping and pressure. Of all these, the latter is the cleanest way of manipulating exchange paths in a system and therefore offers the possibility to dramatically manipulate the ground state. Inelastic neutron scattering is one of the most powerful tools to probe the finger print of non-ordered quantum entangled states: The spin dynamics. Therefore, in combination, pressure and inelastic neutron scattering are a super tool in experimental quantum magnetism. Using the archetypic quantum magnet, SrCu2(BO3)2, we present a number of high-pressure inelastic neutron scattering studies. SrCu2(BO3)2 is the realisation [1] of what is known as the Shastry-Sutherland lattice [2] consisting of a network of spin dimers with exchange interaction J inside the dimer and J’ between the dimers. For low ratios of J’/J, a product of dimer singlets is the ground state. Upon increasing J’/J, a singlet plaquette phase is encountered and finally an ordered antiferromagnetic state is established [3]. The phase diagram of SrCu2(BO3)2 resembles the predicted one remarkably well with phase transitions around 1.8 GPa and 3.0 GPa to enter the plaquette and antiferromagnetic phases respectively [4]. We performed inelastic neutron scattering experiments with high pressures to investigate the nature of the predicted phases and in this way contribute with a piece in the puzzle for understanding many-body quantum physics.

[1] Kageyama et al., Phys. Rev. Lett. 82, 3168-3171 (1999)
[2] B. S. Shastry and B. Sutherland, Physica 108B, 1069-1070 (1981)
[3] P. Corboz and F. Mila, Phys. Rev. B 87, 115144 (2013)
[4] M. E. Zayed et al., Nature Physics 13, 962-966 (2017)

Primary author


Andrea Piovano (ILL) Daniel Gabriel Mazzone (PSI - Paul Scherrer Institut) Ekaterina Pomjakushina (Paul Scherrer Institute) Ellen Fogh (EPFL - EPF Lausanne) Frédéric Mila (EPFL) Gaétan Giriat (EFPL) Gediminas Simutis (PSI - Paul Scherrer Institut) Henrik Rønnow (EPFL) Jakob Lass (PSI - Paul Scherrer Institut) Kazuhisa Kakurai (CROSS) Koji Munakata (CROSS) Maciej Bartkowiak (HZB) Martin Boehm (ILL) Mohamed Zayed (Carnegie Mellon University Qatar) Oleksandr Prokhnenko (HZH) Richard Gaal (EPFL SB ICMP EPSL) Thomas Hansen (ILL)

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