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SUMMARY:Magnetic structure refinement in the Mott insulator NiS$_2$
DTSTART;VALUE=DATE-TIME:20220901T164000Z
DTEND;VALUE=DATE-TIME:20220901T170000Z
DTSTAMP;VALUE=DATE-TIME:20220826T122247Z
UID:indico-contribution-3761@indico.stfc.ac.uk
DESCRIPTION:Speakers: Jonas A. Krieger (Max Planck Institute of Microstruc
 ture Physics)\nWe present muon spin spectroscopy ($\\mu$SR) measurements o
 n the antiferromagnetic Mott insulator NiS$_2$. This compound features two
  subsequent magnetic phase transitions around 38.9K and 29K associated wit
 h the opening of a Mott gap. From the the rotation dependence of transvers
 e field $\\mu$SR measurements (Fig. 1b) we confirm the magnetic space grou
 p 205.33 in the 38.9K to 29K phase\, refined from neutron diffraction $[1]
 $. Using dipolar field calculations\, we identify a candidate muon stoppin
 g site on a 24d Wyckoff position (blue site in Fig. 1b inset). We then cal
 culate the muon stopping sites by using ab-initio density functional theor
 y (DFT) and relaxing a supercell containing a single muon (i.e. hydrogen) 
 impurity. Indeed the lowest energy muon site is found within 0.2 Angstrom 
 of the experimentally determined one (red site in Fig. 1b inset). In addit
 ion\, DFT predicts a second stopping site at an 8c Wyckoff position (green
  site in Fig. 1b inset)\,  that can fully explain a small satellite freque
 ncy that we observe in the spectra. We then use the number of observed fre
 quencies in the low temperature phase as a constraint to exclude magnetic 
 order parameters inconsistent with our results.\n\n$[1]$ S. Yano\, et al.\
 , Phys. Rev. B 93\, 024409 (2016)\n\n![Local field distribution in (a) zer
 o field and (b) transverse field. The curves are offset for clarity. The i
 nset shows the candidate muon stopping sites.][1]\n\n\n  [1]: https://driv
 e.google.com/uc?id=10jCaXwniuyysWzkgiKTmvn_yHxz1PfYW\n\nhttps://indico.stf
 c.ac.uk/event/53/contributions/3761/
LOCATION:Science and Technology Campus\, University of Parma
URL:https://indico.stfc.ac.uk/event/53/contributions/3761/
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