Abstract
A series of Sr(Co1-xNix)2As2 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 aligned in the ab plane and a helimagnetic wave vector of q=(0,0,0.56) for x=0.1. The combination of neutron diffraction and angle-resolved photoemission spectroscopy measurements shows that the tuning of a flat band with dx2-y2 orbital character drives the helimagnetism and indicates the possibility of a quantum order-by-disorder mechanism.
Original language | English |
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Article number | 094446 |
Journal | Physical Review B |
Volume | 100 |
Issue number | 9 |
DOIs | |
State | Published - Sep 30 2019 |
Funding
We are grateful to Dr. D. L. Gong and Dr. L. Y. Xing for the assistance with data analysis and thank Dr. R. Y. Jin, Dr. J. D. Zhang, and Dr. I. Vekhter for helpful discussions. Y.L. would like to thank Dr. S. Li and Dr. H. Luo for providing laboratory equipment for sample growth and Beijing Normal University for sample characterization during his stay in China. Single-crystal growth and the work for neutron scattering were supported by US NSF Grant No. DMR-1700081 and Robert A. Welch Foundation Grant No. C-1839 (P.D.). The MPMS measurements, data analysis, and manuscript preparation were supported by the US Department of Energy under EPSCoR Grant No. DE-SC0012432 with additional support from the Louisiana Board of Regents. The ARPES experiment was performed on the Dreamline beamline, Shanghai Synchrotron Radiation Facility, and supported by the Ministry of Science and Technology of China (Grant No. 2016YFA0401002) and the CAS Pioneer Hundred Talents Program (type C). This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.