Abstract
Heterointerfaces have led to the discovery of novel electronic and magnetic states because of their strongly entangled electronic degrees of freedom. Single-phase chromium compounds always exhibit antiferromagnetism following the prediction of the Goodenough-Kanamori rules. So far, exchange coupling between chromium ions via heteroanions has not been explored and the associated quantum states are unknown. Here, we report the successful epitaxial synthesis and characterization of chromium oxide (Cr2O3)-chromium nitride (CrN) superlattices. Room-temperature ferromagnetic spin ordering is achieved at the interfaces between these two antiferromagnets, and the magnitude of the effect decays with increasing layer thickness. First-principles calculations indicate that robust ferromagnetic spin interaction between Cr3+ ions via anion-hybridization across the interface yields the lowest total energy. This work opens the door to fundamental understanding of the unexpected and exceptional properties of oxide-nitride interfaces and provides access to hidden phases at low-dimensional quantum heterostructures.
| Original language | English |
|---|---|
| Article number | 017202 |
| Journal | Physical Review Letters |
| Volume | 128 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 7 2022 |
Funding
The authors thank Dr. G. Q. Yu and Dr. Z. H. Zhu at the Institute of Physics, Chinese Academy of Sciences, Professor D. Z. Hou, Professor L. F. Wang, and Professor Z. Liao at the University of Science and Technology, Professor Q. Li at Tsinghua University, and Professor H. W. Guo at Fudan University for valuable discussions. This work was supported by the National Key Basic Research Program of China (Grants No. 2019YFA0308500 and No. 2020YFA0309100), the National Natural Science Foundation of China (Grants No. 11974390, No. 52025025, No. 52072400), the Beijing Nova Program of Science and Technology (Grant No. Z191100001119112), Beijing Natural Science Foundation (Z190010, Z200009, and 2202060), the Strategic Priority Research Program of Chinese Academy of Sciences (Grants No. XDB33030200 and No. XDB28030000), and the Guangdong-Hong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology. The PNR experiments were conducted at the Beamline MR of Chinese Spallation Neutron Source, CAS, and partial PNR work were used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the ORNL. XAS experiments were conducted at the Beamline 4B9B of BSRF. XRD measurements were conducted at the beamline 14B1 and 02U2 of SSRF. XMCD measurements were conducted at NSRL in China and SSLS in Singapore. The XPS measurements at PNNL were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award No. 10122. The authors thank Dr. G. Q. Yu and Dr. Z. H. Zhu at the Institute of Physics, Chinese Academy of Sciences, Professor D. Z. Hou, Professor L. F. Wang, and Professor Z. Liao at the University of Science and Technology, Professor Q. Li at Tsinghua University, and Professor H. W. Guo at Fudan University for valuable discussions. This work was supported by the National Key Basic Research Program of China (Grants No. 2019YFA0308500 and No. 2020YFA0309100), the National Natural Science Foundation of China (Grants No. 11974390, No. 52025025, No. 52072400), the Beijing Nova Program of Science and Technology (Grant No. Z191100001119112), Beijing Natural Science Foundation (Z190010, Z200009, and 2202060), the Strategic Priority Research Program of Chinese Academy of Sciences (Grants No. XDB33030200 and No. XDB28030000), and the Guangdong-Hong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology. The PNR experiments were conducted at the Beamline MR of Chinese Spallation Neutron Source, CAS, and partial PNR work were used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the ORNL. XAS experiments were conducted at the Beamline 4B9B of BSRF. XRD measurements were conducted at the beamline 14B1 and 02U2 of SSRF. XMCD measurements were conducted at NSRL in China and SSLS in Singapore. The XPS measurements at PNNL were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award No. 10122.