RESUMO
We report the synthesis of ethylenediamine-intercalated NbSe2 and Li-ethylenediamine-intercalated MoSe2 single crystals with increased interlayer distances and their electronic structures measured by means of angle-resolved photoemission spectroscopy (ARPES). X-ray diffraction patterns and transmission electron microscopy images confirm the successful intercalation and an increase in the interlayer distance. ARPES measurement reveals that intercalated NbSe2 shows an electronic structure almost identical to that of monolayer NbSe2. Intercalated MoSe2 also returns the characteristic feature of the monolayer electronic structure, a direct band gap, which generates sizable photoluminescence even in the bulk form. Our results demonstrate that the properties and phenomena of the monolayer transition metal dichalcogenides can be achieved with large-scale bulk samples by blocking the interlayer interaction through intercalation.
RESUMO
Purely quantum electron systems exhibit intriguing correlated electronic phases by virtue of quantum fluctuations in addition to electron-electron interactions. To realize such quantum electron systems, a key ingredient is dense electrons decoupled from other degrees of freedom. Here, we report the discovery of a pure quantum electron liquid that spreads up to ~3 Å in a vacuum on the surface of an electride crystal. Its extremely high electron density and weak hybridization with buried atomic orbitals show the quantum and pure nature of the electrons, which exhibit a polarized liquid phase, as demonstrated by our spin-dependent measurement. Furthermore, upon enhancing the electron correlation strength, the dynamics of the quantum electrons change to that of a non-Fermi liquid along with an anomalous band deformation, suggestive of a transition to a hexatic liquid crystal phase. Our findings develop the frontier of quantum electron systems and serve as a platform for exploring correlated electronic phases in a pure fashion.
RESUMO
PURPOSE: To compare surgically induced astigmatism (SIA) based on incision site and evaluate the clinical results and astigmatic stability of iris-claw phakic intraocular lens (Artisan lens; Ophtec BV, Groningen, Netherlands) implantation. METHODS: Eighty-five eyes of 53 patients with myopia who underwent Artisan lens implantation with a 6.2-mm incision and follow-up of 6 months were retrospectively observed. SIA was assessed using keratometric astigmatism at 6 months postoperatively for the incision sites of the sclera, limbus, and cornea, and the efficacy, safety, predictability, and astigmatic stability were also calculated. RESULTS: SIA obtained using Naeser's polar method (KP[90]SIA) was -0.48 ± 0.35 for scleral incisions, -0.99 ± 0.35 for limbal incisions, and -1.14 ± 0.54 for corneal incisions. Corresponding net astigmatism values, as calculated with KP(90)SIA and KP(135)SIA, were 0.70 ± 0.48 (177°), 1.04 ± 0.37 (175°), and 1.21 ± 0.57 (1°), respectively, with SIA increasing the nearer the incision was to the cornea center. Six months after surgery, the efficacy index was 1.03 and the safety index was 1.08. Ninety-eight percent of patients were within 1.50 diopters of attempted refraction. CONCLUSIONS: The values of SIA after Artisan lens insertion showed significant differences among three incision locations, despite the absence of significant differences in preoperative steep corneal axis astigmatism values at the incision locations. It would be applicable for refractive surgery in the aspect of minimizing astigmatism after surgery.
