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Charge and Spin Dynamics in DNA Nanomolecules: Modeling and Applications
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Samira Fathizadeh, Sohrab Behnia
Internal interactions and their effects could have substantial effect on the spin–polarized currents. One of the phenomena observed in this case is the spin-Hall effect (SHE). SHE, driven by the spin–orbit interaction, converts a charge current into a pure spin current [82,83]. Spin Hall effect often find use in various applications such as magnetization switching, domain wall motion, spin current detection, etc. On the basis of studying the roles of these effects, it is essential that we pay attention to spin-Hall effect in the DNA chain attached on gold.
Quantum Anomalous Hall Effect in Topological Insulators
Published in Evgeny Y. Tsymbal, Igor Žutić, Spintronics Handbook: Spin Transport and Magnetism, Second Edition, 2019
Abhinav Kandala, Anthony Richardella, Nitin Samarth
Kane and Mele explored what happens in graphene when spin-orbit coupling is considered [4]. The spin-orbit term in the Hamiltonian was found to have a form similar to the staggered field in the Haldane model, except that it was spin-dependent. As in the spin Hall effect, spin-orbit coupling acts like an effective magnetic field that depends on the direction of the spin polarization. This takes the chiral edge state of the spinless Haldane model, and splits it into two oppositely rotating edge states with opposite spins. This was termed the quantum spin Hall (QSH) effect. Further, this state is topologically distinct from an ordinary band insulator, which guarantees that the edge states are robust against disorder (see Chapter 14, Volume 2). It can be characterized by a topological invariant called Z2, which is similar to the Chern number for the QHE state [5]. QSH was also predicted in strained semiconductors with large spin-orbit coupling, and was soon after experimentally observed in the HgTe/CdTe quantum wells [6, 7].
Phase-Sensitive Interface and Proximity Effects in Superconducting Spintronics
Published in Evgeny Y. Tsymbal, Žutić Igor, Spintronics Handbook: Spin Transport and Magnetism, Second Edition, 2019
Another important consequence of spin-orbit coupling is the spin-Hall effect and the inverse spin-Hall effect [190–193], discussed further in Chapter 8, Volume 2 and Chapters 7–9, Volume 3. The spin-Hall effect is the generation of a spin current from a charge current as a result of spin-dependent asymmetric scattering in the presence of spin-orbit interaction. The inverse spin-Hall effect describes the reciprocal effect of a conversion of a spin current into a charge current. In superconductors, such as NbN, these effects are mediated by quasiparticle excitations above the superconducting gap, leading to a strong enhancement of the effects in the superconducting state [194].
Simultaneous harvesting of radiative cooling and solar heating for transverse thermoelectric generation
Published in Science and Technology of Advanced Materials, 2021
Satoshi Ishii, Asuka Miura, Tadaaki Nagao, Ken-ichi Uchida
Figure 1 depicts a schematic of the prepared device which can simultaneously harvest radiative cooling and solar heating to generate thermoelectric voltage by the SSE. The device consists of four layers in order; a substrate, a ferrimagnetic (or ferromagnetic) insulator, a paramagnetic metal, and a light absorber. High transparency in the solar spectrum and high emissivity in the atmospheric window are the necessary conditions for the substrate. Additionally, the ferrimagnetic insulator has to be transparent to sunlight in order not to be heated by the sun. The ferrimagnetic insulator and paramagnetic metal form a spintronic device to generate a spin current by the SSE where ferrimagnetic insulator (paramagnetic metal) acts as a heat-to-spin (spin-to-charge) current converter [7]. The paramagnetic metal converts the SSE-induced spin current to electric voltage by the inverse spin Hall effect (ISHE) [33–35]. The purpose of the light absorber is to absorb sunlight which is not fully absorbed by the paramagnetic metal.
Strongly correlated oxides for energy harvesting
Published in Science and Technology of Advanced Materials, 2018
Jobu Matsuno, Jun Fujioka, Tetsuji Okuda, Kazunori Ueno, Takashi Mizokawa, Takuro Katsufuji
We reviewed recent advances in strongly correlated oxides as thermoelectric materials by focusing on two kinds of approaches. The first one is to enhance the figure of merit of ordinary thermoelectric properties by the following three ways: (i) to enhance the Seebeck coefficient by controlling the orbital degeneracy through carrier doping, (ii) to reduce the phonon thermal conductivity by the fluctuation of the orbital degree of freedom, and (iii) to reduce the phonon thermal conductivity by introducing the interface to the materials. The second one is to use new phenomena such as spin Seebeck effect and anomalous Nernst effect, both of which are dominated by SOC of materials. In Ir oxides containing 5d orbitals with strong SOC, we demonstrated the SOC-related phenomena which potentially contribute to energy harvesting: (i) correlated Dirac/Weyl semimetal, (ii) inverse spin Hall effect, and (iii) interface-driven magnetic skyrmions.
Domain wall motion in multiferroic nanostructures under the influence of spin-orbit torque and nonlinear dissipative effect
Published in Mechanics of Advanced Materials and Structures, 2022
Chiranjeev K. Shahu, Shruti Dubey, Sharad Dwivedi
However, there are a few drawbacks. Some of them are as follows: the possibility to reproduce the DW displacement/translation, depinning of DW from a thermally stable position, and achieving the maximum velocity in the low field/current regime due to the DW structural instability [6–10]. Recently, an approach has been used to tackle these issues by considering the effects of both spin-transfer-torque (STT), and spin-orbit-torque (SOT) observed in multilayer systems [5,11,12]. The STT arises when a spin-polarized current crossing a domain wall (DW) transfers angular momentum to the internal structure of DW, thereby pushing it in the direction of the electron flow [13–15]. On the other hand, SOT exists in systems with structural inversion asymmetry where the electronic energy bands are split by strong spin-orbit coupling. The origin of SOT could be due to two known mechanisms: the Rashba effect and the Spin-Hall effect (SHE). The Rashba effect is generated at the interface between the nonmagnetic heavy metal and the magnetic layer by strong spin-orbit coupling [5,16–19]. On the other hand, the SHE arises when unpolarized electrons flowing through a material with strong spin-orbit coupling (heavy metal) are converted into a perpendicular spin-current. This spin current exerts a torque on the ferromagnetic layer and consequently modifies its magnetization dynamics [20–22]. The recent studies indicate that the SOTs (either Rashba and/or SHE) affects the direction of the DW propagation, DW mobility, threshold and breakdown values of the current density, thus, play a vital role in the development of efficient and fast DW based devices [23–28].