Spin-polarized voltage probes for helical edge state: A model study

The boundary modes of topological insulators are protected by the symmetries of the nontrivial bulk electronic states. Unless these symmetries are broken, they can give rise to novel phenomena, such as the quantum spin Hall effect in one-dimensional (1D) topological edge states, where quasiparticle backscattering is suppressed by time-reversal symmetry (TRS). Here, we investigate the properties of the 1D topological edge state of bismuth in the absence of TRS, where backscattering is predicted to occur. Using spectroscopic imaging and spin-polarized measurements with a scanning tunneling microscope, we compared quasiparticle interference (QPI) occurring in the edge state of a pristine bismuth bilayer with that occurring in the edge state of a bilayer, which is terminated by ferromagnetic iron clusters that break TRS. Our experiments on the decorated bilayer edge reveal an additional QPI branch, which can be associated with spin-flip scattering across the Brioullin zone center between time-reversal band partners. The observed QPI characteristics exactly match with theoretical expectations for a topological edge state, having one Kramer’s pair of bands. Together, our results provide further evidence for the nontrivial nature of bismuth and in particular, demonstrate backscattering inside a helical topological edge state induced by broken TRS through local magnetism.

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Topological Edge States and Transport Properties in Zigzag Stanene Nanoribbons with Magnetism

New Journal of Physics ◽

10.1088/1367-2630/ac4009 ◽

2021 ◽

Author(s):

Xiaolong Lü ◽

Hang Xie

Keyword(s):

Phase Transitions ◽

Electric Field ◽

Transport Properties ◽

Magnetic Phase ◽

Edge State ◽

Magnetic Phase Transitions ◽

Topological Phase ◽

Edge States ◽

Spin Polarized ◽

Topological Phase Transitions

Abstract In this work, we investigate the topological phase transitions and corresponding transport properties in zigzag stanene nanoribbon with different magnetism. The results show that the off-resonant circularly polarized (ORCP) light may induce anisotropic chiral edge state with a magnetic phase transition from antiferromagnetic state to nonmagnetic state. In combination with the ORCP light and electric field, the 100% spin-polarized edge state can be induced with some magnetic orders. The finite-size effect is also an important factor for the magnetic phase transitions, which in turn induces topological phase transitions from the band insulator to topological phases. By constructing the topological-insulator junctions with some topological edge states, we further study the Fabry-Perot resonant, where multiple reflection edge states cause strong current loops. By modulating the ORCP and electric field, the system can also be regarded as a switcher, to control the charge current or spin polarized current. These findings pave a way for designing topological device with magnetic edges in the future nano spintronics.

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$\nu=\frac{2}{3}$ Edge State: A Toy Model Study from Composite Fermion Point of View

Communications in Theoretical Physics ◽

10.1088/0253-6102/32/3/321 ◽

1999 ◽

Vol 32 (3) ◽

pp. 321-326 ◽

Cited By ~ 1

Author(s):

Wei HongDuo ◽

Yu Yue

Keyword(s):

Edge State ◽

Point Of View ◽

Composite Fermion ◽

Model Study

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Spin-polarized Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176976 ◽

1990 ◽

Vol 48 (4) ◽

pp. 768-769

Author(s):

Kazuyuki Koike ◽

Hideo Matsuyama

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Speed ◽

Magnetic Thin Films ◽

Electron Spin Polarization ◽

Acquisition Time ◽

Magnetization Direction ◽

Spin Polarized ◽

Conventional Methods ◽

Scanning Electron

Spin-polarized scanning electron microscopy (spin SEM), where the secondary electron spin polarization is used as the image signal, is a novel technique for magnetic domain observation. Since its first development by Koike and Hayakawa in 1984, several laboratories have extensively studied this technique and have greatly improved its capability for data extraction and its range of applications. This paper reviews the progress over the last few years.Almost all the high expectations initially held for spin SEM have been realized. A spatial resolution of several hundreds angstroms has been attained, which is nearly one order of magnitude higher than that of conventional methods for thick samples. Quantitative analysis of magnetization direction has been performed more easily than with conventional methods. Domain observation of the surface of three-dimensional samples has been confirmed to be possible. One of the drawbacks, a long image acquisition time, has been eased by combining highspeed image-signal processing with high speed scanning, although at the cost of image quality. By using spin SEM, the magnetic structure of a 180 degrees surface Neel wall, magnetic thin films, multilayered films, magnetic discs, etc., have been investigated.

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Social Desirability in Personality Inventories

Journal of Individual Differences ◽

10.1027/1614-0001/a000138 ◽

2014 ◽

Vol 35 (3) ◽

pp. 144-157 ◽

Cited By ~ 12

Author(s):

Martin Bäckström ◽

Fredrik Björklund

Keyword(s):

Social Desirability ◽

Big Five ◽

Work Performance ◽

Factor Model ◽

Five Factor Model ◽

Peer Ratings ◽

Personality Inventories ◽

Model Study ◽

The Difference ◽

New Variables

The difference between evaluatively loaded and evaluatively neutralized five-factor inventory items was used to create new variables, one for each factor in the five-factor model. Study 1 showed that these variables can be represented in terms of a general evaluative factor which is related to social desirability measures and indicated that the factor may equally well be represented as separate from the Big Five as superordinate to them. Study 2 revealed an evaluative factor in self-ratings and peer ratings of the Big Five, but the evaluative factor in self-reports did not correlate with such a factor in ratings by peers. In Study 3 the evaluative factor contributed above the Big Five in predicting work performance, indicating a substance component. The results are discussed in relation to measurement issues and self-serving biases.

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