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We investigate the spin and charge Nernst effect of a four-terminal Aharonov–Bohm interferometer with Rashba spin–orbit interaction (RSOI). It is shown that a pure spin Nernst effect or a fully spin-polarized Nernst effect can be obtained by modulating the magnetic flux phase ϕ and the RSOI induced phase φ. It is also demonstrated that some windows of ϕ (or φ) for maintaining an almost fully spin-polarized Nernst effect exist and their width is under the control of the other phase. Moreover, for the charge Nernst coefficient N c and spin Nernst coefficient N s the relationship N c ( ϕ , φ ) = − N s ( φ , ϕ ) always holds. These results suggest that our proposal may act as a controllable thermospin generator.

High-performance light absorption devices have previously been obtained by coupling photons to conduction electrons. However, energy harvesting is limited in these devices because they only absorb light from one incident direction. We have developed a wide-band bidirectional visible light absorber (BLA) based on a quasi-periodic nanocone array coated with a dielectric-loaded Au monolayer. The proposed BLA is capable of simultaneously absorbing light from both the front and rear surfaces, yielding an average front absorption of 87.4% and a corresponding rear absorptivity of 76.2% in the range 300–700 nm. The bidirectional absorption properties were obtained at incident angles varying from 0 to 60°. Experimental and theoretical analyses indicate that these absorption properties can be ascribed to a combination of the localized cavity resonant mode, the localized surface plasmonic mode, the guided mode resonance, and hybrid coupling between the cavity resonant mode and the surface plasmonic mode. This concept provides a new pathway for the fabrication of new types of flexible or wearable solar thermoelectric devices, photodetectors, or other solid-state devices with large areas.

We theoretically investigate the electron transport through a quantum-dot spin valve subject to a circularly polarized field. It is shown that the original equilibrium spin current arising from the spin Josephson effect can be converted to a charge current by the circularly polarized field. Numerical calculations demonstrate that the sign and the magnitude of the equilibrium spin current can both be deduced from the induced charge current. Moreover, the dependence of the induced charge current on the system parameters is also studied and the most important finding is that for most choices of the system parameters the induced charge current is large enough to be measured by present technology. Therefore, our findings offer a promising way to detect the equilibrium spin current in spin valve systems.

By means of first-principles computations within density functional theory, we systematically investigated the adsorption energy, stable geometry, and magnetic and electronic properties of transition metal (TM) (from Sc to Zn) atoms adsorbed on the MoS2 monolayer. The adsorption energies indicate all the TM atoms are chemically adsorbed on the MoS2 monolayer except for the Zn atom. The results show that the most stable adsorption site is above the Mo atom, while the Sc, Ti and Mn atoms prefer the hollow site of the hexagonal ring formed by the S and Mo atoms. The adsorption energies vary obviously with different TM atoms, which may be related to their number of d electrons. Interestingly, the band structures and magnetic properties of the TM atom adsorbed MoS2 monolayer can be efficiently modified by adsorbing the different TM atoms. Our results indicate the TM atoms adsorbed MoS2 monolayers are excellent candidates for spintronics.

The band-gap modulation of zigzag and armchair graphane-like SiC nanoribbons (GSiCNs) under uniaxial elastic strain is investigated using the density functional theory. The results show that band gap of both structures all decreases when being compressed or tensed. In compression, both zigzag and armchair GSiCNs are semiconductors with a direct band gap. However, in tension, the armchair GSiCNs undergo a direct-to-indirect band-gap transition but the zigzag GSiCNs still have a direct band gap. These results are also proved by HSE06 method. This implies a potential application of the graphane-like SiC nanoribbons in the future pressure sensor and optical electronics nanodevices.

We investigate the transport properties of an interacting ring threaded by a magnetic flux and with Rashba spin-orbit coupling, based on a recently developed functional renormalized group technique. In the calculations of the electronic transport processes, the Coloumb On-site interactions are taken into account. For an interacting ring connected to two leads, we find that (i) for ΦAC = 0, the behavior of transmission zero at ΦAB = π is generic for the universal regime; (ii) for certain ΦAC and ΦAB, one can use the mesoscopic ring as spin filter even in the presence of the local interaction in the ring.

The intriguing electronic and magnetic properties of the fluorinated bilayer SiC sheets are studied using density functional theory. The fluorinated bilayer SiC sheets exhibit diverse electronic and magnetic behaviors: a ferromagnetic half metal for structure I which means that all corresponding carbon and silicon atoms from bilayer sheets have same coordinates of a- and b-axes, while an antiferromagnetic metal with intralayer ferromagnetism for structure II with same coordinates only for silicon atoms, and each carbon atom in one layer facing the center of corresponding hexagon in the other one. The fluorinated bilayer SiC sheets for structure II is more stable than that for structure I. So, controlling different structure types can effectively modulate the electronic and magnetic properties of the fluorinated bilayer SiC sheets, which endows the fluorinated bilayer SiC sheets with great potential applications for future functional nanodevices.

Non-equilibrium Green’s function method is applied to study the spin thermoelectric effects in a four-quantum-dot ring with two of the quantum dots magnetized. The influence of magnetic configuration on the spin thermoelectric transport through the system is investigated. In some magnetic configurations, a significant spin Seebeck coefficient [Formula: see text] can be generated with the variation of the quantum dot (QD) energy level. Appropriately tuning the QD energy level can let the present device work as a pure spin-up (spin-down) or a pure-spin-current thermal generator. The combined effect of the magnetization and magnetic flux (or Rashba spin-orbit coupling) is also investigated. Finally, the charge figure of merit [Formula: see text] and spin figure of merit [Formula: see text] are evaluated, it is found that the magnitude of the spin figure of merit can be comparable to that of the charge counterpart.

We develop a scheme to investigate the flux of nonequilibrium transport based on the full counting statistics and nonequilibrium functional renormalization group method. As an illustrative example, we study the charge transfer in the system of an interacting quantum dot connected to two noninteracting reservoirs via tunneling. Within the lowest approximation in functional renormalization group, we obtain the cumulant generating function analytically.

We investigate the properties of Andreev multiple reflection and supercurrent in a normal-metal junction with a quantum dot embedded in a mesoscopic superconducting ring. The quantum dot is in the Coulomb blockade regime and contains several energy levels. The supercurrent through the junction is created by an external magnetic flux threaded through the ring. The supercurrent is related to the multiple Andreev reflection at interfaces between the superconductor and the normal metal, which is influenced by the Coulomb blockade on the quantum dot. Using a tight-binding model with Bogoliubov-de Gennes pairing potential, the supercurrent versus the external flux is calculated. By switching on the gate voltage applied on the dot, the supercurrent shows a series of peaks and valleys for various values of the flux through the ring. The results suggest the strong effect of the quantum dot on the supercurrent in such a structure, and the possible methods of controlling the supercurrent.

We investigate the flux-dependent Kondo temperature in a quantum wire with local Rashba and Coulomb interactions in the Kondo regime, based on the combination of nonequilibrium Green's function and slave-boson methods. It is found that the Kondo temperature of the device strongly depends on the Rashba phase. When the Rashba phase is equal to π 2 , one can deduce an analytic expression which is similar to the Kondo temperature for a quantum dot connected to electronic reservoirs.

Based on the Bogoliubov–de Gennes equation, we investigate the s-wave superconducting pairing in the presence of the Rashba spin–orbit interaction (SOI). We find that the superconducting is still in the singlet pairing when the spin–orbit interaction is included. The pairing potential is always weakened by the SOI due to its destructive effect on the superconductivity, and the pairing strength shows a periodic-like oscillation as the SOI strength changes. The period reflects the relationship between the characteristic length of SOI and the coherent length of superconductivity. When the disorder is also introduced, the pairing potential fluctuates in the space, but the disorder has less influence on the pairing strength than the SOI does. The fluctuation pattern depends on both the disorder and the strength of SOI, suggesting the spatial precesions of spins due to the SOI.

We theoretically predict the appearance of a persistent charge current in a Rashba ring with a normal and a ferromagnetic lead under no external bias. This charge current is the result of the breaking of the time inversion symmetry in the original persistent pure spin current induced by the Rashba spin-orbit coupling (RSOC) in the ring due to the existence of the ferromagnetic lead. With the Keldysh Green's function technique, we find that not only the magnitude and sign but also the spin polarization of the generated charge current is determined by the system parameters such as the magnetization direction of the ferromagnetic lead, the tunneling coefficient, the strength of the RSOC and the exchange energy of the ferromagnetic lead, which are all tunable in experiments, that is, a controllable persistent spin-polarized charge current can be obtained in such a device.

The advent of holography metasurfaces unlocks a plethora of exciting opportunities for rapid progress at the frontiers of various branches of science and engineering. However, the holography metasurfaces are constrained by sophisticated design and fabrication procedures and are less compatible with dynamic functionalities as well as unequal across the electromagnetic spectrum. Here, a new approach is proposed to fabricate speckle image holography metasurfaces with chaotic carrier fringes for broadband photon management. Using this holography metasurfaces structure allows to sculpt wavefronts of light almost at will. As a proof-of-concept, the incorporation of these structures into white organic light-emitting diodes realizes tunable regional concentrated radiation patterns without spectral distortion. Moreover, the fabricated optical diffusers with the proposed structures also exhibit controllable broadband light softening, resulting in drastically enhanced extra optical gain than that of conventional diffusers. It is hoped that the effort can provide an alternative pathway for precisely broadband beam sculpting and can enable the integration of various optoelectronic systems for practical application.

We theoretically study the spin transport through a two-terminal quantum dot device under the influence of a symmetric spin bias and circularly polarized light. It is found that the combination of the circularly polarized light and the applied spin bias can result in a net charge current. The resultant charge current is large enough to be measured when properly choosing the system parameters. The resultant charge current can be used to deduce the spin bias due to the fact that there exists a simple linear relation between them. When the external circuit is open, a charge bias instead of a charge current can be induced, which is also measurable by present technologies. These findings indicate a new approach to detect the spin bias by using circularly polarized light.

Based on Bogoliubov-de Gennes equation, we investigate the superconducting pairing due to the nearest-neighboring attractive interaction in the presence of the Rashba spin-orbit coupling (SOC). It is found that the superconducting is still of the singlet nature and dominated by the $d$-wave symmetry in the presence of SOC and in the absence of disorder. The pairing strength has decreasing maxima as the SOC strength increases due to its destructive effect on the superconductivity and shows a periodiclike oscillation reflecting the relationship between the characteristic length of SOC and the coherent length of superconductivity. In the presence of SOC and disorder, the pairing has both the singlet and triplet components, and the $s$- and $p$-wave symmetries are induced in addition to the dominant $d$-wave symmetry. The related strengths of different pairing components exhibit complicated dependence on the strengths of the SOC and the disorder.

By solving the Schr\"odinger equation for degenerate exciton states identically interacting with LO phonons we are able to analytically show that the composite states can be grouped into collective and individual sets with two different energies. The optical transition for the individual set is prohibited but this prohibition can be partially removed by spreading of off-diagonal exciton-phonon coupling in a system with many exciton states. As a result, every satellite peak in the phonon sidebands of photoluminescence is split into a two-peak structure corresponding to these two sets. The model can be associated with excitons bound to deep donor centers in wide-gap semiconductors and provides a natural explanation for the peak splitting observed in the phonon sidebands of these materials.