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Research into the magnetism of antimony overlayers on a ferromagnetic substrate is presented. This approach produces a layer-specific analysis of the spin polarization. The relatively long range of the Sb spin polarization is attributable to the semimetallic nature of the Sb overlayer.

Measurement of the quantum-mechanical phase in quantum matter provides the most direct manifestation of the underlying abstract physics. We used resonant x-ray scattering to probe the relative phases of constituent atomic orbitals in an electronic wave function, which uncovers the unconventional Mott insulating state induced by relativistic spin-orbit coupling in the layered 5d transition metal oxide Sr2IrO4. A selection rule based on intra-atomic interference effects establishes a complex spin-orbital state represented by an effective total angular momentum = ½ quantum number, the phase of which can lead to a quantum topological state of matter. [ABSTRACT FROM AUTHOR]

The antiferromagnetic structure of Sr3Ir207, the bilayer analog of a spin-orbital Mott insulator Sr2IrO4, was revealed by resonant magnetic x-ray diffraction. Contrasting intensities of the magnetic diffraction at the IrIII and LII edges show a Jeff = 1/2 character of the magnetic moment as is argued in Sr2IrO4. The magnitude of moment, however, was found to be smaller than that of Sr2IrO4 by a factor of 5 to 6. implying that Sr3Ir2O7 is no longer a Mott insulator but a weak antiferromagnet. An evident change of the temperature dependence of the resistivity at TN, from almost temperature-independent resistivity to insulating, strongly suggests that the emergent weak magnetism controls the charge gap. The magnetic structure was found to be an out-of-plane collinear antiferromagnetic ordering in contrast to the in-plane canted antiferromagnetism in Sr2IrO4, originating from the strong bilayer antiferromagnetic coupling. [ABSTRACT FROM AUTHOR]

We have studied the surface composition and structure of colossal magneto-resistive perovskite thin films of La0.65Pb0.35MnO3. Depending on the annealing treatments, the thin film surface exhibits wildly different behavior and composition. With a gentle annealing procedure, the surface is dominated by appreciable Pb segregation, whereas a heavily annealed surface undergoes an irreversible restructuring into a Ruddlesden–Popper phase (La1−xPbx)2MnO4. The measured effective Debye temperatures of the two surfaces shows that the Pb-rich La0.65Pb0.35MnO3 surface region is softer than the surface of the Ruddlesden–Popper phase. [Copyright &y& Elsevier]

While induced spin polarization of a palladium (Pd) overlayer on antiferromagnetic and magneto-electric Cr 2 O 3 (0001) is possible because of the boundary polarization at the Cr 2 O 3 (0001), in the single domain state, the Pd thin film appears to be ferromagnetic on its own, likely as a result of strain. In the conduction band, we find the experimental evidence of ferromagnetic spin polarized in Pd thin films on a Cr 2 O 3 (0001) single crystal, especially in the thin limit, Pd thickness of around 1-4 nm. Indeed there is significant spin polarization in 10 Å thick Pd films on Cr 2 O 3 (0001) at 310 K, i.e. above the Néel temperature of bulk Cr 2 O 3 . While Cr 2 O 3 (0001) has surface moments that tend to align along the surface normal, for Pd on Cr 2 O 3 , the spin polarization contains an in-plane component. Strain in the Pd adlayer on Cr 2 O 3 (0001) appears correlated to the spin polarization measured in spin polarized inverse photoemission spectroscopy. Further evidence for magnetization of Pd on Cr 2 O 3 is provided by measurement of the exchange bias fields in Cr 2 O 3 /Pd(buffer)/[Co/Pd] n exchange bias systems. The magnitude of the exchange bias field is, over a wide temperature range, virtually unaffected by the Pd thickness variation between 1 and 2 nm., (Creative Commons Attribution license.)

In this review, an attempt has been made to compare the electronic structures of various 5d iridates (iridium oxides), with an effort to note the common features and differences. Both experimental studies, especially angle-resolved photoemission spectroscopy (ARPES) results, and first-principles band structure calculations have been discussed. This brings to focus the fact that the electronic structures and magnetic properties of the high-Z 5d transition iridates depend on the intricate interplay of strong electron correlation, strong (relativistic) spin-orbit coupling, lattice distortion, and the dimensionality of the system. For example, in the thin film limit, SrIrO 3 exhibits a metal-insulator transition that corresponds to the dimensionality crossover, with the band structure resembling that of bulk Sr 2 IrO 4 .

Multi-functional thin films of boron (B) doped Cr 2 O 3 exhibit voltage-controlled and nonvolatile Néel vector reorientation in the absence of an applied magnetic field, H. Toggling of antiferromagnetic states is demonstrated in prototype device structures at CMOS compatible temperatures between 300 and 400 K. The boundary magnetization associated with the Néel vector orientation serves as state variable which is read via magnetoresistive detection in a Pt Hall bar adjacent to the B:Cr 2 O 3 film. Switching of the Hall voltage between zero and non-zero values implies Néel vector rotation by 90 degrees. Combined magnetometry, spin resolved inverse photoemission, electric transport and scanning probe microscopy measurements reveal B-dependent T N and resistivity enhancement, spin-canting, anisotropy reduction, dynamic polarization hysteresis and gate voltage dependent orientation of boundary magnetization. The combined effect enables H = 0, voltage controlled, nonvolatile Néel vector rotation at high-temperature. Theoretical modeling estimates switching speeds of about 100 ps making B:Cr 2 O 3 a promising multifunctional single-phase material for energy efficient nonvolatile CMOS compatible memory applications.

Photocurrent production in quasi-one-dimensional (1D) transition-metal trichalcogenides, TiS 3 (001) and ZrS 3 (001), was examined using polarization-dependent scanning photocurrent microscopy. The photocurrent intensity was the strongest when the excitation source was polarized along the 1D chains with dichroic ratios of 4:1 and 1.2:1 for ZrS 3 and TiS 3 , respectively. This behavior is explained by symmetry selection rules applicable to both valence and conduction band states. Symmetry selection rules are seen to be applicable to the experimental band structure, as is observed in polarization-dependent nanospot angle-resolved photoemission spectroscopy. Based on these band symmetry assignments, it is expected that the dichroic ratios for both materials will be maximized using excitation energies within 1 eV of their band gaps, providing versatile polarization sensitive photodetection across the visible spectrum and into the near-infrared.

The band structures of the transition metal dichalcogenides (TMD's) 2H-MoS 2 (0001) and 2H-WSe 2 (0001), before and after palladium adsorption, were investigated through angle-resolved photoemission. Palladium adsorption on 2H-MoS 2 (0001) is seen to result in very different band shifts than seen for palladium on 2H-WSe 2 (0001). The angle resolved photoemission results of palladium adsorbed on WSe 2 (0001) indicate that palladium accepts electron density from substrate. The resulting band shift will lead to a decrease in the barriers to the hole injection. The opposite band shifts occur upon palladium adsorption between 2H-MoS 2 (0001). The overall trend is consistent with the deposition of other metals deposited on TMD's, except that for palladium adsorption on MoS 2 (0001), there is an increase in the MoS 2 (0001) substrate band gap with palladium adsorption, as is evident from the combination of photoemission and inverse photoemission., (© 2020 IOP Publishing Ltd.)

The band structure of the quasi-one-dimensional transition metal trichalcogenide ZrS 3 (001) was investigated using nanospot angle resolved photoemission spectroscopy (nanoARPES) and shown to have many similarities with the band structure of TiS 3 (001). We find that ZrS 3 , like TiS 3 , is strongly n-type with the top of the valence band ∼1.9 eV below the Fermi level, at the center of the surface Brillouin zone. The nanoARPES spectra indicate that the top of the valence band of the ZrS 3 (001) is located at [Formula: see text]. The band structure of both TiS 3 and ZrS 3 exhibit strong in-plane anisotropy, which results in a larger hole effective mass along the quasi-one-dimensional chains than perpendicular to them.