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Dynamical Bond Formation in KNi 2 Se 2
Author(s) -
Neilson James R.,
FryPetit Allyson M.,
Drichko Natalia,
Stone Matthew B.,
Llobet Anna,
Balasubramanian Mahalingam,
Suchomel Matthew R.,
McQueen Tyrel M.
Publication year - 2022
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202200042
Subject(s) - tetragonal crystal system , monoclinic crystal system , atom (system on chip) , dipole , metal , materials science , instability , density functional theory , chemical physics , molecular physics , crystallography , condensed matter physics , chemistry , computational chemistry , physics , crystal structure , quantum mechanics , embedded system , organic chemistry , computer science , metallurgy
Emphanisis, or the appearance out of nothing, has been used to describe the phenomena of spontaneous atom off‐centering and dipole formation at elevated temperatures in lead chalcogenides. Here, we provide spectroscopic evidence of spontaneous formation of metal‐metal bonds above T ∼50 K in the layered metal KNi 2 Se 2 . These bonds form zig‐zag chains that lower the local symmetry from tetragonal to monoclinic. Energy‐resolved pair distribution function measurements exclude a pure phonon origin of our observations, and instead imply the existence of extra, slowly fluctuating, Ni−Ni bonds above T =50 K. Density functional theory calculations support this lower symmetry configuration as an instability of tetragonal KNi 2 Se 2 . We thus demonstrate that the phenomena of emphansis is not limited to local electric dipole formation, but can also be driven by the formation of metal‐metal bonds.