Resonant Inelastic X-ray Scattering study of the charge density wave phase of 1T-TaS₂

The low temperature ground state of 1T-TaS₂ continues to draw attention .The onset of a commensurate charge density wave (CDW) order results in a low energy electronic structure with an odd number of electrons per unit cell. Thus, the increasing resistivity and anomalously small magnetic susceptibility have been regarded as evidence for a Mott insulating phase that could host spin liquid physics [1]. However, there is growing evidence that cooling rate-dependent CDW [2] stacking faults can induce a much more trivial groundstate in bulk 1T-TaS₂ [3]. Interestingly, recent scanning tunneling spectroscopy measurements revealed the existence of localized spins in mono-layer samples of isostructural 1T-TaSe₂ [3]. Here we present our recent temperature-, Q- and energy-dependent Resonant Inelastic X-ray Scattering study at the Ta L₃-edge of bulk 1T-TaS₂. We discuss our results in relation to the proposed groundstate scenarios.

[1] Law, K. T. and Lee, P. A., PNAS July 3, 2017 114 (27) 6996-7000
[2] Wang, Y. D et al, Nature Communications 11, 4215 (2020)
[3] Ritschel, T et al, Phys. Rev. B 98, 195134
[4] Ruan, W. et al, arXiv:2009.07379