Epitaxially Stabilized EuMoO3: A New Itinerant Ferromagnet

Synthesizing metastable phase often opens new functions in materials but is a challenging topic. Thin film techniques have advantages to form materials which do not exist in nature since nonequilibrium processes are frequently utilized. In this study, we successfully synthesize epitaxially stabilized new compound of perovskite Eu2+Mo4+O3 as a thin film form by a pulsed laser deposition. Analogous perovskite SrMoO3 is a highly conducting paramagnetic material, but Eu2+ and Mo4+ are not compatible in equilibrium and previous study found more stable pyrochlore Eu23+Mo24+O7 prefers to form. By using isostructural perovskite substrates, the gain of the interface energy between the film and the substrate stabilizes the matastable EuMoO3 phase. This compound exhibits high conductivity and large magnetic moment, originating from Mo 4d2 electrons and Eu 4f7 electrons, respectively. Our result indi-cates the epitaxial stabilization is effective not only to stabilize crystallographic structures but also to from a new compound which contains unstable combinations of ionic valences in bulk form.Comment: 7 pages, 9 figure

Band Structure and Spin–Orbital Texture of the (111)‐KTaO3(111)‐KTaO_{3} 2D Electron Gas

2D electron gases (2DEGs) in oxides show great potential for the discoveryof new physical phenomena and at the same time hold promise for electronicapplications. In this work, angle-resolved photoemission is used to determinethe electronic structure of a 2DEG stabilized in the (111)-oriented surface ofthe strong spin–orbit coupling material KTaO3. The measurements revealmultiple sub-bands that emerge as a consequence of quantum confinementand form a sixfold symmetric Fermi surface. This electronic structure is wellreproduced by self-consistent tight-binding supercell calculations. Based onthese calculations, the spin and orbital texture of the 2DEG is determined.It is found that the 2DEG Fermi surface is derived from bulk J = 3/2 statesand exhibits an unconventional anisotropic Rashba-like lifting of the spindegeneracy.Spin-momentum locking holds only for high-symmetry directionsand a strong out-of-plane spin component renders the spin texture threefoldsymmetric. It is found that the average spin-splitting on the Fermi surfaceis an order of magnitude larger than in SrTiO3, which should translateinto an enhancement in the spin–orbitronic response of (111)-KTaO3 2DEGbaseddevices

Band Structure and Spin–Orbital Texture of the (111)‐KTaO₃ 2D Electron Gas

2D electron gases (2DEGs) in oxides show great potential for the discovery of new physical phenomena and at the same time hold promise for electronic applications. In this work, angle-resolved photoemission is used to determine the electronic structure of a 2DEG stabilized in the (111)-oriented surface of the strong spin–orbit coupling material KTaO3. The measurements reveal multiple sub-bands that emerge as a consequence of quantum confinement and form a sixfold symmetric Fermi surface. This electronic structure is well reproduced by self-consistent tight-binding supercell calculations. Based on these calculations, the spin and orbital texture of the 2DEG is determined. It is found that the 2DEG Fermi surface is derived from bulk J = 3/2 states and exhibits an unconventional anisotropic Rashba-like lifting of the spin- degeneracy. Spin-momentum locking holds only for high-symmetry directions and a strong out-of-plane spin component renders the spin texture threefold symmetric. It is found that the average spin-splitting on the Fermi surface is an order of magnitude larger than in SrTiO3, which should translate into an enhancement in the spin–orbitronic response of (111)-KTaO3 2DEG- based devices

Epitaxially Stabilized EuMoO₃: A New Itinerant Ferromagnet

Synthesizing metastable phases often open new functions in materials, but it is a challenging topic. Thin film techniques have advantages to form materials which do not exist in nature since nonequilibrium processes are frequently utilized. In this study, we successfully synthesize an epitaxially stabilized new compound of perovskite Eu²⁺Mo⁴⁺O₃ as a thin film form by a pulsed laser deposition. The analogous perovskite SrMoO₃ is a highly conducting paramagnetic material, but Eu²⁺ and Mo⁴⁺ are not compatible in equilibrium, and a previous study found that the more stable pyrochlore Eu₂³⁺Mo₂⁴⁺O₇ prefers to form. By using isostructural perovskite substrates, the gain of the interface energy between the film and the substrate stabilizes the matastable EuMoO₃ phase. This compound exhibits high conductivity and large magnetic moment, originating from Mo 4d² electrons and Eu 4f⁷ electrons, respectively. Our result indicates the epitaxial stabilization is effective not only to stabilize crystallographic structures but also to form a new compound which contains unstable combinations of ionic valences in bulk form