Barlowite: The next quantum spin liquid?*

Barlowite, Cu₄(OH)₆BrF, is a newly reported quantum spin liquid (QSL) host material, containing “perfect” kagomé layers separated by interlayer Cu²⁺ ions, with reports that Zn²⁺ substitution for Cu²⁺ induces a QSL ground state. In this talk, we will report on the crystal growth and a comprehensive suite of measurements, including x-ray and neutron diffraction, NMR, specific heat, and magnetization that resolve the ambiguities of the previously reported disorder on the interlayer sites, and provide a quantitative comparison of the physics of Barlowite to other synthetic Cu²⁺ kagomé minerals. These results pave the way to discovery of S=1/2 kagomé realizations with minimal interlayer coupling effects.