| 1. |
- Annese, Emilia, et al.
(författare)
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Nonvortical Rashba Spin Structure on a Surface with C1h Symmetry
- 2016
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Ingår i: Physical Review Letters. - 0031-9007. ; 117:1
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Tidskriftsartikel (refereegranskat)abstract
- A totally anisotropic peculiar Rashba-Bychkov (RB) splitting of electronic bands was found on the Tl/Si(110)-(1×1) surface with C1h symmetry by angle- and spin-resolved photoelectron spectroscopy and first-principles theoretical calculation. The constant energy contour of the upper branch of the RB split band has a warped elliptical shape centered at a k point located between Γ and the edge of the surface Brillouin zone, i.e., at a point without time-reversal symmetry. The spin-polarization vector of this state is in-plane and points almost the same direction along the whole elliptic contour. This novel nonvortical RB spin structure is confirmed as a general phenomenon originating from the C1h symmetry of the surface.
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| 2. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 3. |
- Sakamoto, Kazuyuki, et al.
(författare)
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Abrupt Rotation of the Rashba Spin to the Direction Perpendicular to the Surface
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:9, s. 096805-
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Tidskriftsartikel (refereegranskat)abstract
- The polarization vector of the Rashba spin, which must be parallel to the two-dimensional (2D) plane in an ideal system, is found to change abruptly and definitely to the direction perpendicular to the surface at the K̅ point of the Brillouin zone of a real hexagonal system, the Tl/Si(111)-(1×1) surface. This finding obtained experimentally by angle-resolved and spin-resolved photoemission measurements is fully confirmed by a first-principles theoretical calculation. We found that the abrupt rotation of the Rashba spin is simply understood by the 2D symmetry of the hexagonal structure.
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| 4. |
- Sakamoto, Kazuyuki, et al.
(författare)
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Symmetry induced peculiar Rashba effect on thallium adsorbed Si(111) surfaces
- 2015
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier. - 0368-2048 .- 1873-2526. ; 201, s. 88-91
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Tidskriftsartikel (refereegranskat)abstract
- The geometric symmetry of the surface plays an important role for the spin-orbit-induced spin texture of two-dimensional electronic states. This article reviews the peculiar Rashba spins induced by a C-3 symmetry, including the completely spin polarized surface states with the polarization vector oriented perpendicular to the surface, i.e. a direction that is not expected in a typical Rashba system. This review also describes that this peculiar Rashba situation has possibility to suppress backscattering and therefore to greatly improve the efficiency of spin transport, which is an essential issue in the development of high-performance semiconductor spintronic devices. (C) 2014 Elsevier B.V. All rights reserved.
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| 5. |
- Sakamoto, Kazuyuki, et al.
(författare)
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Valley spin polarization by using the extraordinary Rashba effect on silicon
- 2013
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Ingår i: Nature Communications. - : Nature Publishing Group: Nature Communications. - 2041-1723. ; 4:2073
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Tidskriftsartikel (refereegranskat)abstract
- The addition of the valley degree of freedom to a two-dimensional spin-polarized electronic system provides the opportunity to multiply the functionality of next-generation devices. So far, however, such devices have not been realized due to the difficulty to polarize the valleys, which is an indispensable step to activate this degree of freedom. Here we show the formation of 100% spin-polarized valleys by a simple and easy way using the Rashba effect on a system with C-3 symmetry. This polarization, which is much higher than those in ordinary Rashba systems, results in the valleys acting as filters that can suppress the backscattering of spin-charge. The present system is formed on a silicon substrate, and therefore opens a new avenue towards the realization of silicon spintronic devices with high efficiency.
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