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Rotational symmetry breaking at the incommensurate charge-density-wave transition in Ba(Ni,Co)2(As,P)2: Possible nematic phase induced by charge/orbital fluctuations

Merz, Michael; Wang, Liran; Wolf, Thomas; Nagel, Peter; Meingast, Christoph; Schuppler, Stefan

Abstract (englisch):
Nematic phase transitions in high-temperature superconductors have a strong impact on the electronic properties of these systems. BaFe2As2, with an established nematic transition around 137 K induced by magnetic fluctuations, and BaNi2As2, a nonmagnetic analog of BaFe2As2 with a structural transition in the same temperature range, share a common tetragonal aristotype crystal structure with space-group type I4/mmm. In contrast to BaFe2As2 where collinear stripe magnetic order is found for the orthorhombic low-T phase, a unidirectional charge density wave together with (distorted) zigzag chains are observed for the triclinic low-T phase of BaNi2As2. Here we show that between the high- and low-T phases of Ba(Ni,Co)2(As,P)2 an additional phase with broken fourfold symmetry and dxz orbital order exists which is a promising candidate for charge/orbital-fluctuation-induced nematicity. Moreover, our data suggest that the enhanced Tc found for Ba(Ni,Co)2(As,P)2 for higher Co or P substitution levels might result from suppression of the (distorted) zigzag chains by reducing the contribution of the dxy orbitals.


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Originalveröffentlichung
DOI: 10.1103/PhysRevB.104.184509
Zugehörige Institution(en) am KIT Institut für Quantenmaterialien und -technologien (IQMT)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 11.2021
Sprache Englisch
Identifikator ISSN: 2469-9950, 2469-9969
KITopen-ID: 1000140076
HGF-Programm 47.11.02 (POF IV, LK 01) Emergent Quantum Phenomena
Erschienen in Physical Review B
Verlag American Physical Society (APS)
Band 104
Heft 18
Seiten Artikl.Nr.: 184509
Vorab online veröffentlicht am 16.11.2021
Nachgewiesen in Scopus
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