Numerical Studies of the Kitaev-Gamma Model Under a Magnetic Field

Recently, there has been excitement generated around α-RuCl₃ as a candidate for the material realization of the Kitaev spin liquid (KSL). Beyond the dominant ferromagnetic (FM) Kitaev interaction, subleading spin interactions are required to explain the zig-zag (ZZ) magnetic ordering and behaviour of α-RuCl₃ under a magnetic field. On the basis of exact diagonalization (ED) and DMRG, an antiferromagnetic (AFM) Gamma interaction was found to be essential for stabilizing the KSL under tilted magnetic fields. A subsequent classical study of the Kitaev-Gamma model found a multitude of large unit cell magnetic orders due to the competition between Gamma and the applied field. Furthermore, an infinite tensor product state (iTPS) study found that these classical orders are melted by quantum fluctuations, giving way to two nematic paramagnetic states. The topological nature of these nematic phases and their relation to the KSL remain unknown. Here we present results obtained with ED to address these open questions.