A New Synthetic Quantum Spin Liquid Candidate CCO111*

Quantum spin liquid is a new state of quantum strongly correlated topological matter characterized by the presence of a Mott gap, topological order and fictionalized spectrum of spin excitations. Despite the tremendous progress in bulk synthesis of potential QSL candidates the `smoking-gun' compound remains elusive. Here, we present a new synthetic candidate QSL material successfully templated from (111)-oriented CoCr₂O₄ by pulsed laser deposition. Remarkably, as the thickness is reduced to four Kagome-triangular atomic planes, the magnetic ground state suddenly switches from a spiral order to the quantum paramagnetic regime with no sign of long-range spin ordering down to 30 mK and 9T. At the same time, the frustration factor rises by almost three orders of magnitude indicating the first realization of a quantum spin liquid state on the new artificial lattice. Our findings open the opportunities of achieving novel ultra-quantum states of matter in a broad class of synthetic materials.