%0 Journal Article %1 PhysRevB.108.L241117 %A Niggemann, Nils %A Astrakhantsev, Nikita %A Ralko, Arnaud %A Ferrari, Francesco %A Maity, Atanu %A Müller, Tobias %A Richter, Johannes %A Thomale, Ronny %A Neupert, Titus %A Reuther, Johannes %A Iqbal, Yasir %A Jeschke, Harald O. %D 2023 %I American Physical Society %J Phys. Rev. B %K b %N 24 %P L241117 %R 10.1103/PhysRevB.108.L241117 %T Quantum paramagnetism in the decorated square-kagome antiferromagnet Na$_6$Cu$_7$BiO$_4$(PO$_4$)Cl$_3$ %U https://link.aps.org/doi/10.1103/PhysRevB.108.L241117 %V 108 %X The square-kagome lattice Heisenberg antiferromagnet is a highly frustrated Hamiltonian whose material realizations have been scarce. We theoretically investigate the recently synthesized Na6Cu7BiO4(PO)4)4Cl3 where a Cu2+ spin-1/2 square-kagome lattice (with a six site unit cell) is decorated by a seventh magnetic site alternatingly above and below the layers. The material does not show any sign of long-range magnetic order down to 50 mK despite a Curie-Weiss temperature of −212K indicating a quantum paramagnetic phase. Our DFT energy mapping elicits a purely antiferromagnetic Hamiltonian that features longer range exchange interactions beyond the pure square-kagome model and, importantly, we find the seventh site to be strongly coupled to the plane. We combine two variational Monte Carlo approaches, pseudofermion/Majorana functional renormalization group and Schwinger-Boson mean field calculations to show that the complex Hamiltonian of Na6Cu7BiO4(PO)4)4Cl3 still features a nonmagnetic ground state. We explain how the seventh Cu2+ site actually aids the stabilization of the disordered state. We predict static and dynamic spin structure factors to guide future neutron scattering experiments.

@article{PhysRevB.108.L241117, abstract = {The square-kagome lattice Heisenberg antiferromagnet is a highly frustrated Hamiltonian whose material realizations have been scarce. We theoretically investigate the recently synthesized Na6Cu7BiO4(PO)4)4Cl3 where a Cu2+ spin-1/2 square-kagome lattice (with a six site unit cell) is decorated by a seventh magnetic site alternatingly above and below the layers. The material does not show any sign of long-range magnetic order down to 50 mK despite a Curie-Weiss temperature of −212K indicating a quantum paramagnetic phase. Our DFT energy mapping elicits a purely antiferromagnetic Hamiltonian that features longer range exchange interactions beyond the pure square-kagome model and, importantly, we find the seventh site to be strongly coupled to the plane. We combine two variational Monte Carlo approaches, pseudofermion/Majorana functional renormalization group and Schwinger-Boson mean field calculations to show that the complex Hamiltonian of Na6Cu7BiO4(PO)4)4Cl3 still features a nonmagnetic ground state. We explain how the seventh Cu2+ site actually aids the stabilization of the disordered state. We predict static and dynamic spin structure factors to guide future neutron scattering experiments.}, added-at = {2024-02-21T15:53:14.000+0100}, author = {Niggemann, Nils and Astrakhantsev, Nikita and Ralko, Arnaud and Ferrari, Francesco and Maity, Atanu and M\"uller, Tobias and Richter, Johannes and Thomale, Ronny and Neupert, Titus and Reuther, Johannes and Iqbal, Yasir and Jeschke, Harald O.}, biburl = {https://www.bibsonomy.org/bibtex/2a54c127eada89e7fb9fc0a5505e2190d/ctqmat}, day = 19, doi = {10.1103/PhysRevB.108.L241117}, interhash = {b498cc4cdd4dfd3cea2a74268eccc781}, intrahash = {a54c127eada89e7fb9fc0a5505e2190d}, journal = {Phys. Rev. B}, keywords = {b}, month = {12}, number = 24, numpages = {6}, pages = {L241117}, publisher = {American Physical Society}, timestamp = {2024-02-21T15:53:14.000+0100}, title = {Quantum paramagnetism in the decorated square-kagome antiferromagnet Na$_{\mathbf{6}}$Cu$_{\mathbf{7}}$BiO$_{\mathbf{4}}$(PO$_{\mathbf{4}}$)Cl$_{\mathbf{3}}$}, url = {https://link.aps.org/doi/10.1103/PhysRevB.108.L241117}, volume = 108, year = 2023 }