Atomic-scale inversion of spin polarization at an organic-antiferromagnetic interface

Caffrey, Nuala M.; Ferriani, P.; Marocchi, Simone; Heinze, Stefan

doi:10.1103/physrevb.88.155403

Cited by 34 publications

(35 citation statements)

References 58 publications

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“…As shown in 3D spatial distributions of spin polarization (Fig. 3d), Ti 15 O 32 exhibits a large area of negative spatial spin polarization (SSP) in the supercell, which indicates a small possibility of spin polarization reversal in the real space 41 . However, for the defected Ti 35 O 72 with lower Ti vacancies (2.78%), it shows much lower spin polarization than Ti 15 O 32 at the Fermi level ( Supplementary Fig.…”

Section: Resultsmentioning

confidence: 82%

“…The Brillouin Zone is sampled with Γ-centered 3 × 3 × 3 k point meshes for TiO 2 . The spatial spin polarization (SSP) is defined as: Pðr; z; εÞ ¼ n " s ðr; z; εÞ À n # s ðr; z; εÞ n " s ðr; z; εÞ þ n # s ðr; z; εÞ ð1Þ where the n "ð#Þ s ðr; z; εÞ is the spin-up (down) charge density in the real space with an energy interval of [ε, E F ] 41 . In this work, the energy range of [E F -0.2 eV, E F ] is used (see the effect of energy ranges on SSP results in Supplementary Fig.…”

Section: Methodsmentioning

confidence: 99%

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Manipulating spin polarization of titanium dioxide for efficient photocatalysis

et al. 2020

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Photocatalysis has been regarded as a promising strategy for hydrogen production and highvalue-added chemicals synthesis, in which the activity of photocatalyst depends significantly on their electronic structures, however the effect of electron spin polarization has been rarely considered. Here we report a controllable method to manipulate its electron spin polarization by tuning the concentration of Ti vacancies. The characterizations confirm the emergence of spatial spin polarization among Ti-defected TiO 2 , which promotes the efficiency of charge separation and surface reaction via the parallel alignment of electron spin orientation. Specifically, Ti 0.936 O 2 , possessing intensive spin polarization, performs 20-fold increased photocatalytic hydrogen evolution and 8-fold increased phenol photodegradation rates, compared with stoichiometric TiO 2. Notably, we further observed the positive effect of external magnetic fields on photocatalytic activity of spin-polarized TiO 2 , attributed to the enhanced electron-spin parallel alignment. This work may create the opportunity for tailoring the spin-dependent electronic structures in metal oxides.

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Section: Resultsmentioning

confidence: 82%

Section: Methodsmentioning

confidence: 99%

Manipulating spin polarization of titanium dioxide for efficient photocatalysis

et al. 2020

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“…In the past few years molecular spintronics [1] research has witnessed a fast developing interest in the investigation and functionalization of organic-ferromagnetic interfaces [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Major achievements in the field include the detection of the inversion of the spin-polarization above single molecules deposited on magnetic surfaces [7,8,12,16], the measurement of interface magnetoresistance due to the formation of a hybrid interface magnetic layer [11], and the time-resolved occupation analysis of hybrid interface states acting as spindependent electron traps [10].…”

Section: Introductionmentioning

confidence: 99%

Magnetic subunits within a single molecule–surface hybrid

et al. 2017

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Magnetic molecule-surface hybrids are ideal building blocks for molecular spintronic devices due to their appealing tailorable magnetic properties and nanoscale size. So far, assemblies of interacting molecular-surface hybrids needed for spintronic functionality were generated by depositing aromatic molecules onto transition-metal surfaces, resulting in a random arrangement of hybrid magnets due to the inherent and strong hybridization. Here, we demonstrate the formation of multiple intramolecular subunits within a single molecule-surface hybrid by means of spin-polarized scanning tunneling microscopy experiments and ab initio density functional theory calculations. This novel effect is realized by depositing a polycyclic aromatic molecule on a magnetic surface. A highly asymmetric chiral adsorption position induces different structural, electronic, and magnetic properties in each aromatic ring of the molecule. In particular, the induced molecular spin polarization near the Fermi energy varies among the rings due to site-and spin-dependent molecule-surface hybridization. Our results showcase a possible organic chemistry route of tailoring geometrically welldefined assemblies of magnetically distinguishable subunits in molecule-surface hybrids.

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“…The central result of this work stems from the fact that the adatom's LDOS inherits the magnetic noncollinearity of the Mn SS as a consequence of hybridization of the atom's wave function with the substrate. The breaking of the translational symmetry of the spin space within the atom can be introduced, in its simplest form, as a continuous linear variation of the magnetic quantization axis above the adsorbed object [24]: θ (x [110] ) − θ Co = φ(x − x Co )/w, x Co being the position of the atom center and φ/w represents the rotation pitch of the quantization axis within the atom's apparent size. The inset in Fig.…”

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confidence: 99%

Spin-sensitive shape asymmetry of adatoms on noncollinear magnetic substrates

et al. 2016

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The spin-resolved density of states of Co atoms on a noncollinear magnetic support displays a distinct shape contrast, which is superimposed on the regular height contrast in spin-polarized scanning tunneling microscopy. The apparent atom height follows the well-known cosine dependence on the angle formed by the tip and adatom local magnetization directions, whereas the shape contrast exhibits a sine dependence. We explain this effect in terms of a noncollinear spin density induced by the substrate, which in our case is the spin spiral of the Mn monolayer on W(110). The two independent contrast channels, apparent height and shape, are identified with the Co magnetization projections onto two orthogonal axes. As a result, all components of the overall atom magnetic moment vector can be determined with a single spin-sensitive tip in the absence of an external magnetic field. This result should be general for any atom deposited on noncollinear magnetic layers. DOI: 10.1103/PhysRevB.93.125424The control of the spin degree of freedom down to the single-atom limit is nowadays a central research issue [1][2][3][4][5][6][7], fostered by the increasing need for miniaturization and lowering power consumption in communication technologies. The most suitable technique to address the problem is spinpolarized scanning tunneling microscopy (SP-STM) [8], which has proven to be an excellent tool to perform single-atom magnetometry [1,6]. The design of magnetic structures with a given functionality calls for atomic-scale engineering by means of atomic manipulation or self-assembly of lowdimensional structures. Both of them can be combined with SP-STM [6,7,9,10]. For that reason, getting insight into the underlying physics of SP-STM and extending its range of applications is of crucial relevance. The SP-STM principle is the magneto-conductance effect in magnetic tunnel junctions [8,[11][12][13][14], and relies on probing the imbalance between majority and minority spins in the local density of states (LDOS) with respect to a particular magnetic quantization axis. Following the same notation as in Ref. [15], the spinpolarized tunneling current at sample bias V readswhere ρ T and P T are the tip's density of states and spin polarization,ρ s andm s the integrated sample total density of states and magnetization at r (tip position), and θ the angle formed between the tip and local sample magnetization. As a consequence, a SP-STM tip is only sensitive to the projection onto its magnetization direction, m s cos θ , and not to all other components ofm s . Here we show that the situation is radically different if the substrate's magnetic ground state is noncollinear within the spatial extent of an atomic wave function. Owing to the breaking of translational symmetry in spin space associated with the noncollinearity, the atoms' apparent shapes become distorted in spin-resolved STM images. We find that the strength of such distortion provides a quantitative measurement of the total spin component orthogonal to the default sensitivity direct...

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Atomic-scale inversion of spin polarization at an organic-antiferromagnetic interface

Cited by 34 publications

References 58 publications

Manipulating spin polarization of titanium dioxide for efficient photocatalysis

Manipulating spin polarization of titanium dioxide for efficient photocatalysis

Magnetic subunits within a single molecule–surface hybrid

Spin-sensitive shape asymmetry of adatoms on noncollinear magnetic substrates

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