Abstract
Haldane topological materials contain unique antiferromagnetic chains with symmetry-protected energy gaps. Such materials have potential applications in spintronics and future quantum computers. Haldane topological solids typically consist of spin-1 chains embedded in extended three-dimensional (3D) crystal structures. Here, we demonstrate that [Ni(μ−4,4′-bipyridine)(μ-oxalate)]n (NiBO) instead adopts a two-dimensional (2D) metal-organic framework (MOF) structure of Ni2+ spin-1 chains weakly linked by 4,4′-bipyridine. NiBO exhibits Haldane topological properties with a gap between the singlet ground state and the triplet excited state. The latter is split by weak axial and rhombic anisotropies. Several experimental probes, including single-crystal X-ray diffraction, variable-temperature powder neutron diffraction (VT-PND), VT inelastic neutron scattering (VT-INS), DC susceptibility and specific heat measurements, high-field electron spin resonance, and unbiased quantum Monte Carlo simulations, provide a detailed, comprehensive characterization of NiBO. Vibrational (also known as phonon) properties of NiBO have been probed by INS and density-functional theory (DFT) calculations, indicating the absence of phonons near magnetic excitations in NiBO, suppressing spin-phonon coupling. The work here demonstrates that NiBO is indeed a rare 2D-MOF Haldane topological material.
| Original language | English |
|---|---|
| Article number | 5454 |
| Journal | Nature Communications |
| Volume | 14 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2023 |
Funding
The US National Science Foundation (CHE-2055499 to Z.-L.X.) and a Shull Wollan Center Graduate Research Fellowship (to P.T.) are acknowledged for partial support of the research. Part of this work was performed at the National High Magnetic Field Laboratory which is supported by NSF Cooperative Agreement No. DMR-1644779 and the State of Florida. Magnetic property study was conducted in part at the Center for Nanophase Materials Sciences, which was sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Neutron scattering experiments were conducted at ORNL′s Spallation Neutron Source, which is supported by the Scientific User Facilities Division, Office of Basic Energy Sciences (BES), U.S. Department of Energy (DOE), under Contract No. DE-AC0500OR22725 with UT Battelle, LLC. The computing resources were made available through the VirtuES and the ICEMAN projects, funded by Laboratory Directed Research and Development program and Compute and Data Environment for Science (CADES) at ORNL. We acknowledge support by the Deutsche Forschungsgemeinschaft (DFG) through Grant No. WE/3649/4-2 of the FOR 1807 and RTG 1995 (to S.W.), and thank the IT Center at RWTH Aachen University and JSC Jülich for access to computing time through JARA CSD. The authors thank Dr. Phattananawee Nalaoh for help with SCXRD and Dr. Andrzej Ozarowski for help with HFESR interpretation. Department of Chemistry and Open Publishing Support Fund at the University of Tennessee-Knoxville are acknowledged for open access to this research. The US National Science Foundation (CHE-2055499 to Z.-L.X.) and a Shull Wollan Center Graduate Research Fellowship (to P.T.) are acknowledged for partial support of the research. Part of this work was performed at the National High Magnetic Field Laboratory which is supported by NSF Cooperative Agreement No. DMR-1644779 and the State of Florida. Magnetic property study was conducted in part at the Center for Nanophase Materials Sciences, which was sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Neutron scattering experiments were conducted at ORNL′s Spallation Neutron Source, which is supported by the Scientific User Facilities Division, Office of Basic Energy Sciences (BES), U.S. Department of Energy (DOE), under Contract No. DE-AC0500OR22725 with UT Battelle, LLC. The computing resources were made available through the VirtuES and the ICEMAN projects, funded by Laboratory Directed Research and Development program and Compute and Data Environment for Science (CADES) at ORNL. We acknowledge support by the Deutsche Forschungsgemeinschaft (DFG) through Grant No. WE/3649/4-2 of the FOR 1807 and RTG 1995 (to S.W.), and thank the IT Center at RWTH Aachen University and JSC Jülich for access to computing time through JARA CSD. The authors thank Dr. Phattananawee Nalaoh for help with SCXRD and Dr. Andrzej Ozarowski for help with HFESR interpretation. Department of Chemistry and Open Publishing Support Fund at the University of Tennessee-Knoxville are acknowledged for open access to this research.
| Funders | Funder number |
|---|---|
| Center for Nanophase Materials Sciences | |
| Compute and Data Environment for Science | |
| Scientific User Facilities Division | |
| National Science Foundation | DMR-1644779, CHE-2055499 |
| U.S. Department of Energy | DE-AC0500OR22725 |
| Basic Energy Sciences | |
| Oak Ridge National Laboratory | |
| Laboratory Directed Research and Development | |
| University of Tennessee, Knoxville | |
| State of Florida | |
| Deutsche Forschungsgemeinschaft | RTG 1995 |