Hidden spin-orbital texture at the $\bar{\Gamma }$-located valence band maximum of a transition metal dichalcogenide semiconductor

Abstract

Finding stimuli capable of driving an imbalance of spin-polarised electrons within a solid is the central challenge in the development of spintronic devices. However, without the aid of magnetism, routes towards this goal are highly constrained with only a few suitable pairings of compounds and driving mechanisms found to date. Here, through spin- and angle-resolved photoemission along with density functional theory, we establish how the $p$-derived bulk valence bands of semiconducting 1T-HfSe${}_2$ possess a local, ground-state spin texture spatially confined within each Se-sublayer due to strong sublayer-localised electric dipoles orientated along the $c$-axis. This hidden spin-polarisation manifests in a `coupled spin-orbital texture' with in-equivalent contributions from the constituent $p$-orbitals. While the overall spin-orbital texture for each Se sublayer is in strict adherence to time-reversal symmetry (TRS), spin-orbital mixing terms with net polarisations at time-reversal invariant momenta are locally maintained. These apparent TRS-breaking contributions dominate, and can be selectively tuned between with a choice of linear light polarisation, facilitating the observation of pronounced spin-polarisations at the Brillouin zone centre for all $k_z$. We discuss the implications for the generation of spin-polarised populations from 1T-structured transition metal dichalcogenides using a fixed energy, linearly polarised light source.

11 pages, 6 figures

References in corpus (9)

• Valley polarization in MoS2 monolayers by optical pumping
• Classification of stable three-dimensional Dirac semimetals with nontrivial topology
• Van der Waals heterostructures for spintronics and opto-spintronics
• Current induced electron spin polarization in strained semiconductors
• Two energy gaps and Fermi surface 'arcs' in NbSe2
• Selective probing of hidden spin-polarized states in inversion-symmetric bulk MoS2
• Observation of a uniaxial strain-induced phase transition in the 2D topological semimetal IrTe${}_2$
• Angle-resolved photoemission spectroscopy of perovskite-type transition-metal oxides and their analyses using tight-binding band structure
• A general route to form topologically-protected surface and bulk Dirac fermions along high-symmetry lines

Cited by in corpus (4)

• Geometry-induced spin-filtering in photoemission maps from WTe${}_2$ surface states
• Spin-Valley Locking in 2H-TaS2 and Its Co-Intercalated Counterpart: Roles of Surface Domains and Co Intercalation
• Spin-orbital mixing in the topological ladder of the two-dimensional metal PtTe${}_2$
• Designer three-dimensional electronic bands in asymmetric transition metal dichalcogenide heterostructures