Enhanced superconductivity induced by several-unit-cells diffusion in an FeTe/FeSe bilayer heterostructure

Abstract

Enhanced superconductivity induced by several-unit-cells diffusion in an FeTe/FeSe bilayer heterostructure. Physical Review B: Covering condensed matter and materials physics, 99 (6), 064502-1-064502-1.

Induced Superconducting Transition in Ultra-Thin Iron-Selenide Films by a Mg-Coating Process

“…It is in sharp contrast to the pristine #UFM0 with a semiconducting behavior that is consistent with the case of other ultrathin Fe-chalcogenide thin films prepared by PLD and magnetron sputtering methods [21,25,31]. A similar phenomena of T c revival in 8 nm non-superconducting FeSe thin films has been already observed in one of previous work in which a FeTe coating layer was introduced [32]. Here, for the case of T c triggered in Mg-coated FeSe ultra-thin films, we prefer to deduce a possibility of a universal origin, which is attributed to a varied electronic orbital structure and a possibly lower electron occupancy [27] in Fe orbital near Mg/FeSe interfacial region [32].…”

“…A similar phenomena of T c revival in 8 nm non-superconducting FeSe thin films has been already observed in one of previous work in which a FeTe coating layer was introduced [32]. Here, for the case of T c triggered in Mg-coated FeSe ultra-thin films, we prefer to deduce a possibility of a universal origin, which is attributed to a varied electronic orbital structure and a possibly lower electron occupancy [27] in Fe orbital near Mg/FeSe interfacial region [32]. The temperature dependence of resistivity under external field up to 6 T (parallel to c-axis) is shown in Figure 2b with the results of #UFM3 given as an example.…”

“…Darker contrast indicates higher intensity of the characteristic edges. EELS results are very sensitive in distinguishing different elements because that the mode of orbital excitation in every element is unique [ 32 , 38 , 39 ]. In addition to the Mg coating on the top of FeSe layer which was verified by EDS-mappings, a region with the presence of both Mg- K and Se- K edges was distinguished near the Mg/FeSe interface.…”

Free-standing 2D non-van der Waals antiferromagnetic hexagonal FeSe semiconductor: halide-assisted chemical synthesis and Fe2+ related magnetic transitions

“…The transition-metal 3d states can be revealed by measuring the integrated intensity of the white lines directly. 35 As shown in Fig. 3c , the ratio of L 3 /L 2 was 4.6, suggesting the presence of some Fe 3+ .…”

Near-Infrared Reflectivity of Superconducting FeSe Thin Films

“…It is known that the superconductivity and electric conductance depend strongly on carrier concentration [28], [29] and electronic relaxation time induced by scattering centers. When the condition ωτ∼1 is satisfied, with ω being the radiation frequency, the response of electrons in an electronic system to optical irradiation can be observed so that the optical coefficients such as optical transmission and reflection along with corresponding optical conductivity are the functional form of the radiation frequency.…”