This study reports experimental evidence that α-RuCl₃ exhibits quantum spin liquid (QSL) behavior similar to the Kitaev model on a honeycomb lattice, a topological quantum spin liquid system. The material is highly amenable to neutron scattering experiments, making it a promising candidate for studying Kitaev physics. The research confirms strong spin-orbit coupling and a low-temperature magnetic order that matches predictions for a QSL phase. The study also explains some puzzling results through stacking faults inherent to the 2D nature of the material. Dynamical response functions, especially at energies and temperatures where interlayer effects are not significant, are consistent with deconfinement physics expected for QSLs. The authors compare their results with calculated dynamics from gauge flux excitations and Majorana fermions of the pure Kitaev model, proposing α-RuCl₃ as a prime candidate for experimental realization of fractionalized Kitaev physics. The Kitaev model describes spin-1/2 moments on a honeycomb lattice with anisotropic couplings. The Hamiltonian includes both Kitaev (K) and Heisenberg (J) interactions. The pure Kitaev model (J=0) is stable for small Heisenberg perturbations. The Hamiltonian has been proposed to describe octahedrally-coordinated magnetic systems with dominant spin-orbit coupling. The study focuses on α-RuCl₃, which has a honeycomb lattice and strong spin-orbit coupling, making it a promising material for Kitaev physics. The material's magnetic structure is characterized by a trigonal lattice with weak interlayer bonding. Neutron diffraction shows low-temperature magnetic order with two ordered phases. The magnetic moments are exceptionally low, consistent with a near-liquid-like quantum state. The study confirms strong spin-orbit coupling in α-RuCl₃, which is essential for generating the Kitaev term. The spin-orbit coupling λ is extracted from neutron measurements, showing values close to the expected free-ion value. The material's magnetic excitations are analyzed using inelastic neutron scattering, revealing two branches of excitations. The lower branch (M₁) is centered near 4 meV and shows a minimum near Q = 0.62 Å⁻¹, consistent with a quasi-2D magnetic system. The higher energy mode (M₂) is centered near 6.5 meV. The magnetic modes show different thermal behaviors, with M₁ softening dramatically above the Néel temperature, while M₂ remains unaffected. The results are compared with linear spin-wave theory, showing discrepancies that suggest non-linear dynamical effects and strong quantum fluctuations. The study concludes that α-RuCl₃ is proximate to the QSL phase, with the M₂ mode likely arising from fractionalized Majorana fermion excitations. The results support the presence of Kitaev QSL physics in α-RThis study reports experimental evidence that α-RuCl₃ exhibits quantum spin liquid (QSL) behavior similar to the Kitaev model on a honeycomb lattice, a topological quantum spin liquid system. The material is highly amenable to neutron scattering experiments, making it a promising candidate for studying Kitaev physics. The research confirms strong spin-orbit coupling and a low-temperature magnetic order that matches predictions for a QSL phase. The study also explains some puzzling results through stacking faults inherent to the 2D nature of the material. Dynamical response functions, especially at energies and temperatures where interlayer effects are not significant, are consistent with deconfinement physics expected for QSLs. The authors compare their results with calculated dynamics from gauge flux excitations and Majorana fermions of the pure Kitaev model, proposing α-RuCl₃ as a prime candidate for experimental realization of fractionalized Kitaev physics. The Kitaev model describes spin-1/2 moments on a honeycomb lattice with anisotropic couplings. The Hamiltonian includes both Kitaev (K) and Heisenberg (J) interactions. The pure Kitaev model (J=0) is stable for small Heisenberg perturbations. The Hamiltonian has been proposed to describe octahedrally-coordinated magnetic systems with dominant spin-orbit coupling. The study focuses on α-RuCl₃, which has a honeycomb lattice and strong spin-orbit coupling, making it a promising material for Kitaev physics. The material's magnetic structure is characterized by a trigonal lattice with weak interlayer bonding. Neutron diffraction shows low-temperature magnetic order with two ordered phases. The magnetic moments are exceptionally low, consistent with a near-liquid-like quantum state. The study confirms strong spin-orbit coupling in α-RuCl₃, which is essential for generating the Kitaev term. The spin-orbit coupling λ is extracted from neutron measurements, showing values close to the expected free-ion value. The material's magnetic excitations are analyzed using inelastic neutron scattering, revealing two branches of excitations. The lower branch (M₁) is centered near 4 meV and shows a minimum near Q = 0.62 Å⁻¹, consistent with a quasi-2D magnetic system. The higher energy mode (M₂) is centered near 6.5 meV. The magnetic modes show different thermal behaviors, with M₁ softening dramatically above the Néel temperature, while M₂ remains unaffected. The results are compared with linear spin-wave theory, showing discrepancies that suggest non-linear dynamical effects and strong quantum fluctuations. The study concludes that α-RuCl₃ is proximate to the QSL phase, with the M₂ mode likely arising from fractionalized Majorana fermion excitations. The results support the presence of Kitaev QSL physics in α-R