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arXiv · 1907.09342

Flat band magnetism and helical magnetic order in Ni-doped SrCo$_2$As$_2$

Yu Li·Zhonghao Liu·Zhuang Xu·Yu Song·Yaobo Huang·Dawei Shen·Ni Ma·Ang Li·Songxue Chi·Matthias Frontzek·Huibo Cao·Qingzhen Huang·Weiyi Wang·Yaofeng Xie·Yan Rong·David P. Young·J. F. DiTusa·Pengcheng Dai
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Abstract

A series of Sr(Co$_{1-x}$Ni$_x$)$_2$As$_2$ single crystals was synthesized allowing a comprehensive phase diagram with respect to field, temperature, and chemical substitution to be established. Our neutron diffraction experiments revealed a helimagnetic order with magnetic moments ferromagnetically (FM) aligned in the $ab$ plane and a helimagnetic wavevector of $q=(0,0,0.56)$ for $x$ = 0.1. The combination of neutron diffraction and angle-resolved photoemission spectroscopy (ARPES) measurements show that the tuning of a flat band with $d_{x^2-y^2}$ orbital character drives the helimagnetism and indicates the possibility of a quantum order-by-disorder mechanism.

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Yu Li, Zhonghao Liu, Zhuang Xu, Yu Song, Yaobo Huang, Dawei Shen, Ni Ma, Ang Li, Songxue Chi, Matthias Frontzek, Huibo Cao, Qingzhen Huang, Weiyi Wang, Yaofeng Xie, Yan Rong, David P. Young, J. F. DiTusa, Pengcheng Dai. 2019-07-22. Flat band magnetism and helical magnetic order in Ni-doped SrCo$_2$As$_2$. https://doi.org/10.1103/physrevb.100.094446

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