Journal Article

PUBDB-2024-00088

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png High-pressure phase diagram of BaNi$_2$As$_2$: Unconventional charge density waves and structural phase transitions

Lacmann, T. L. (Corresponding author)Extern* ; Haghighirad, A.-A. (Corresponding author)Extern* ; Souliou, S. M.Extern* ; Merz, M.Extern* ; Garbarino, G. ; Glazyrin, K.XFEL.EU*DESY* ; Heid, R. ; Le Tacon, M. (Corresponding author)

2023
Inst. Woodbury, NY

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Please use a persistent id in citations: doi:10.1103/PhysRevB.108.224115  doi:10.3204/PUBDB-2024-00088

Abstract: Structural phase transitions accompanied by incommensurate and commensurate charge density wave (CDW) modulations of unconventional nature have been reported in BaNi$_2$As$_2$, a nonmagnetic cousin of the parent compound of Fe-based superconductors, BaFe$_2$As$_2$. The strong dependence of the structural and CDW transitions of BaNi$_2$As$_2$ on isoelectronic substitutions alongside original dynamical lattice effects suggests strong tunability of the electronic phase of the system through structural effects. Here, we present a comprehensive synchrotron x-ray diffraction and first-principles calculation study of the evolution of the crystal structure and lattice instabilities of BaNi$_2$As$_2$ as a function of temperature and hydrostatic pressure (up to 12 GPa). We report a cascade of pressure-induced structural phase transitions and electronic instabilities up to ≈10 GPa, above which all CDW superstructures disappear. We reveal that the stable high-pressure phase consists of planar Ni zigzag chains, from which the surrounding As atoms have been pushed away. This yields a strong reduction of the interlayer As-As distance (along the original c axis), akin to what is observed in the collapsed tetragonal structure of other pnictides, albeit here with a monoclinic structure. The discovery of polymorphs in the pressure-temperature phase diagram of BaNi$_2$As$_2$ emphasizes the importance of the relative Ni-Ni and Ni-As bond lengths in controlling the electronic ground state of this compound and increases our understanding of viable electronic phases under extreme conditions.

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)
2. Experimentebetreuung PETRA III (FS-PET-D)

Research Program(s):

1. 631 - Matter – Dynamics, Mechanisms and Control (POF4-631) (POF4-631)
2. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
3. FS-Proposal: I-20200263 (I-20200263) (I-20200263)
4. DFG project 441231589 - Wechselspiel zwischen Ladungsordnung und magnetischer Ordnung in Seltenen-Erd-Nickeldicarbiden. (441231589) (441231589)
5. DFG project 444821420 - Elastische Kontrolle von konkurrierenden Ordnungen in korrelierten Supraleitern (B03) (444821420) (444821420)

Experiment(s):

1. PETRA Beamline P02.2 (PETRA III)

Appears in the scientific report 2023

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Electronics and Telecommunications Collection ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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