Direct experimental observation of the molecular Jeff=3/2 ground state in the lacunar spinel GaTa4Se8

Abstract

Strong spin-orbit coupling lifts the degeneracy of t2g orbitals in 5d transition-metal systems, leaving a Kramers doublet and quartet with effective angular momentum of Jeff = 1/2 and 3/2, respectively. These spin-orbit entangled states can host exotic quantum phases such as topological Mott state, unconventional superconductivity, and quantum spin liquid. The lacunar spinel GaTa4Se8 was theoretically predicted to form the molecular Jeff = 3/2 ground state. Experimental verification of its existence is an important first step to exploring the consequences of the Jeff = 3/2 state. Here, we report direct experimental evidence of the Jeff = 3/2 state in GaTa4Se8 by means of excitation spectra of resonant inelastic x-rays scattering at the Ta L3 and L2 edges. We found that the excitations involving the Jeff = 1/2 molecular orbital were suppressed only at the Ta L2 edge, manifesting the realization of the molecular Jeff = 3/2 ground state in GaTa4Se8.

25 pages, 5 figures + Supplementary Materials [10 pages, 5 figures]

References in corpus (13)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Twisted Hubbard Model for Sr2IrO4: Magnetism and Possible High Temperature Superconductivity
• Fermi Arcs in a Doped Pseudospin-1/2 Heisenberg Antiferromagnet
• Monte Carlo study of an unconventional superconducting phase in Ir-oxide J_{eff}=1/2 Mott insulators induced by carrier doping
• Microscopic study of spin-orbit-induced Mott insulator in Ir oxides
• Ferromagnetism in the Mott insulator Ba2NaOsO6
• Dimensionality Driven Spin-Flop Transition in Layered Iridates
• Robustness of basal-plane antiferromagnetic order and the $J_{eff}=1/2$ state in single-layer iridate spin-orbit Mott insulators
• Spin liquid behaviour in Jeff=1/2 triangular lattice Ba3IrTi2O9
• Electric Pulse Induced Resistive Switching, Electronic Phase Separation, and Possible Superconductivity in a Mott insulator
• First-Order Insulator-to-Metal Mott Transition in the Paramagnetic 3D System GaTa4Se8
• Spin-orbit coupling, strong correlation, and insulator-metal transitions: the J${}_{\mathrm{eff}}$ =3\2 ferromagnetic Mott insulator Ba${}_2$NaOsO${}_6$

Cited by in corpus (2)

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• Charge density functional plus $U$ calculation of lacunar spinel GaM${}_4$Se${}_8$ (M = Nb, Mo, Ta, and W)