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arXiv · 1907.09316

Sign-switching of dimer correlations in SrCu$_2$(BO$_3$)$_2$ under hydrostatic pressure

Simon Bettler·Lena Stoppel·Zewu Yan·Severian Gvasaliya·Andrey Zheludev
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Abstract

Magnetic and vibrational excitations in SrCu$_2$(BO$_3$)$_2$ are studied using Raman spectroscopy at hydrostatic pressures up to 34 kbar and temperatures down to 2.6 K. The frequency of a particular optical phonon, the so-called pantograph mode, shows a very strong anomalous temperature dependence below about 40 K. We link the magnitude of the effect to the magnetic exchange energy on the dimer bonds in the Sutherland-Shastry spin lattice in this material. The corresponding dimer spin correlations are quantitatively estimated and found to be strongly pressure dependent. At around P$_2\sim$22 kbar they switch from antiferromagnetic to being predominantly ferromagnetic.

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Simon Bettler, Lena Stoppel, Zewu Yan, Severian Gvasaliya, Andrey Zheludev. 2019-07-22. Sign-switching of dimer correlations in SrCu$_2$(BO$_3$)$_2$ under hydrostatic pressure. https://doi.org/10.1103/physrevresearch.2.012010

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