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Chirality is a manifestation of the asymmetry inherent in nature. It has been defined as the symmetry breaking of the parity of static objects, and the definition was extended to dynamic motion such that true and false chiralities were distinguished. Recently, rotating, yet not propagating, atomic motions were predicted and observed in two-dimensional materials, and they were referred to as ‘chiral phonons’. A natural development would be the discovery of truly chiral phonons that propagate while rotating in three-dimensional materials. Here we used circularly polarized Raman scattering and first-principles calculations to identify truly chiral phonons in chiral bulk crystals. This approach enabled us to determine the chirality of a crystal in a non-contact and non-destructive manner. In addition, we demonstrated that the law of the conservation of pseudo-angular momentum holds between circularly polarized photons and chiral phonons. These findings are expected to help develop ways for transferring the pseudo-angular momentum from photons to electron spins via propagating chiral phonons in opto-phononic-spintronic devices.

In Part I of this diptych, we outline the parallel mode of differential phase contrast (TEM-DPC), which uses real-space distortion of Fresnel images arising from electrostatic or magnetostatic fields to quantify the phase gradient of samples with some degree of structural contrast. We present an analysis methodology and the associated software tools for the TEM-DPC method and, using them together with numerical simulations, compare the technique to the widely used method of phase recovery based on the transport-of-intensity equation (TIE), thereby highlighting the relative advantages and limitations of each. The TEM-DPC technique is particularly suitable for in situ studies of samples with significant structural contrast and, as such, complements the TIE method since structural contrast usually hinders the latter, but is an essential feature that enables the former. In Part II of this work, we apply the theory and methodology presented to the analysis of experimental data to gain insight into two-dimensional magnetic phase transitions., Microscopy and Microanalysis, 27 (5), ISSN:1431-9276, ISSN:1435-8115

Carrier modulation in transition-metal dichalcogenides (TMDCs) is of importance for applying electronic devices to tune their transport properties and controlling phases, including metallic to superconductivity. Although the surface charge transfer doping method has shown a strong modulation ability of the electronic structures in TMDCs and a degenerately doped state has been proposed, the details of the electronic states have not been elucidated, and this transport behavior should show a considerable thickness dependence in TMDCs. In this study, we characterize the metallic transport behavior in the monolayer and multilayer MoS

We performed a chirality-controlled crystal growth of transition metal disilicide NbSi$_{2}$ and TaSi$_{2}$ by using a laser-diode-heated floating zone (LDFZ) method. The crystal chirality was evaluated in the crystals of centimeters in length by performing single crystal X-ray diffraction as well as probing a spin polarization originating from chirality-induced spin selectivity (CISS) effect. The crystals of right-handed NbSi$_{2}$ and of left-handed TaSi$_{2}$ were obtained in the conventional LDFZ crystal growth, while the left-handed NbSi$_{2}$ and right-handed TaSi$_{2}$ crystals were grown by the LDFZ method with the composition-gradient feed rods. The spin polarization via the CISS was observed over centimeters in the NbSi$_{2}$ single crystals and the sign of the CISS signals was dependent on the chirality of crystals. The correlation between the crystal chirality and CISS signals indicates that the CISS measurements work as a non-destructive method for chirality determination even in centimeter-long specimens., Comment: 9 pages, 6 figures

We report that spin polarization occurs over millimeters in polycrystalline bulk samples of chiral disilicide NbSi$_2$ and TaSi$_2$. As previously demonstrated in the experiments using single crystals of NbSi$_2$ and TaSi$_2$, electrical transport measurements allow detection of direct and inverse signals associated with the chirality-induced spin polarization even in the chiral polycrystals. The spin polarization signals also appear in nonlocal measurements, in which charge current flows only in the area millimeters away from the detection electrode. These data mean that the spin polarization phenomena occur regardless of the presence of crystalline grains in the polycrystals, indicating a robustness and resilience of the chirality-induced spin polarization. On the basis of the experimental data, we found that the sum rule holds for the spin transport signals. A distribution of handedness over the samples was determined on average in the polycrystals. While the mechanism of preserving the spin polarization over millimeters remains to be clarified, the present study may open up prospects of spin control and manipulation over macroscopic length scales using chiral materials., 6 pages, 5 figures

A spin-polarized state is examined under charge current at room temperature without magnetic fields in chiral disilicide crystals NbSi_{2} and TaSi_{2}. We found that a long-range spin transport occurs over ten micrometers in these inorganic crystals. A distribution of crystalline grains of different handedness is obtained via location-sensitive electrical transport measurements. The sum rule holds in the conversion coefficient in the current-voltage characteristics. A diamagnetic nature of the crystals supports that the spin polarization is not due to localized electron spins but due to itinerant electron spins. A large difference in the strength of antisymmetric spin-orbit interaction associated with 4d electrons in Nb and 5d ones in Ta is oppositely correlated with that of the spin polarization. A robust protection of the spin polarization occurs over long distances in chiral crystals.

Chiral plasmonic nanostructures enable ≤pg detection and characterization of biomaterials. The sensing capabilities are associated with the chiral asymmetry of the near fields, which locally can be greater than equivalent circularly polarized light, a property referred to as superchirality. However, sensing abilities do not simply scale with the magnitude of superchirality. We show that chiral molecular sensing is correlated to the thickness of a nanostructure. This observation is reconciled with a previously unconsidered interference mechanism for the sensing phenomenon. It involves the “dissipation” of optical chirality into chiral material currents through the interference of fields generated by two spatially separated chiral modes. The presence of a chiral dielectric causes an asymmetric change in the phase difference, resulting in asymmetric changes to chiroptical properties. Thus, designing a chiral plasmonic sensor requires engineering a substrate that can sustain both superchiral fields and an interference effect.

We investigated microwave propagation in the chiral spin soliton lattice (CSL) phase of micrometer-sized crystals of the monoaxial chiral helimagnet CrNb₃S₆. An advantage of the CSL is that its periodicity can be reconfigured over a macroscopic length scale by means of an external magnetic field. Using a two-antenna microwave spectroscopy technique, we measured the anisotropic response of the transmitted microwaves via the spin dynamics of the CSL. When propagating along the direction parallel to the helical axis, the microwave amplitude increased up to a factor of twenty with decreasing the number of chiral soliton kinks. When the propagation direction was rotated by 90 degrees with regards to the helical axis, the microwave amplitude increased by one order of magnitude upon formation of the chiral helimagnetic order in the vicinity of zero magnetic field, exceeding that of the ferromagnetic phase above the critical field. Our findings open a novel route for controlling the characteristics of microwave propagation using noncollinear spin textures.

We grew thin films of a heavy fermion chiral magnet YbNi$_3$Al$_9$ by using molecular beam epitaxy. They were grown on $c$-plane sapphire substrates under ultra-high vacuum while maintaining a deposition rate at a stoichiometric ratio among Yb, Ni, and Al. The resulting thin films contain epitaxial grains with a $c$ axis parallel to the substrate surface: The YbNi$_3$Al$_9$ $c$ axis is parallel to the sapphire $b$ or $a$ axis. The temperature dependence of the resistivity exhibits a typical feature of a dense Kondo system with a broad shoulder structure at $\sim$40\,K, as well as a kink as a signature of the chiral helimagnetic ordering at 3.6\,K. These features are consistent with those previously observed in bulk samples. The shift in the kink associated with the field-induced phase transition is found in the magnetoresistance curves under a magnetic field applied in the direction perpendicular to the $c$-axis. The magnetic phase diagram well reproduces that for the bulk crystals, implying that the chiral soliton lattice phase arises under magnetic fields, even in thin films.

In Part I of this diptych, we outlined the theory and an analysis methodology for quantitative phase recovery from real-space distortions of Fresnel images acquired in the parallel mode of transmission electron microscopy (TEM). In that work, the properties of the method, termed TEM-differential phase contrast (TEM-DPC), were highlighted through the use of simulated data. In this work, we explore the use of the TEM-DPC technique with experimental cryo-TEM images of a thin lamella of a low temperature two-dimensional (2-D) ferromagnetic material, K$_2$CuF$_4$, to perform two tasks. First, using images recorded below the ordering temperature, we compare the TEM-DPC method to the transport of intensity one for phase recovery, and discuss the relative advantages the former has for experimental data. Second, by tracking the induction of the sample as it is driven through a phase transition by heating, we extract estimates for the critical temperature and critical exponent of the order parameter. The value of the latter is consistent with the 2-D XY class, raising the prospect that a Kosterlitz--Thoules transition may have occurred., Comment: 12 pages, 5 figures. Experimental study following theory and analysis in arXiv:2104.06769

We consider the case of a chiral soliton lattice subjected to uniaxial elastic strain applied perpendicular to the chiral axis and derive through analytical modelling the phase diagram of magnetic states supported in the presence of an external magnetic field. The strain induced anisotropies give rise to three distinct non-trivial spin textures, depending on the nature of the strain, and we show how these states may be identified by their signatures in Lorentz transmission electron microscopy (TEM). Experimental TEM measurements of the Fresnel contrast in a strained sample of the prototypical monoaxial chrial helimagnet CrNb$_3$S$_6$ are reported and compare well with the modelled contrast. Our results demonstrate an additional degree of freedom that may be used to tailor the magnetic properties of helimagnets for fundamental research and applications in the areas of spintronics and the emerging field of strain manipulated spintronics., Comment: 13 pages, 6 figures. Minor style and reference edits

Chirality-induced spin transport phenomena are investigated at room temperature without magnetic fields in a monoaxial chiral dichalcogenide CrNb_{3}S_{6}. We found that spin polarization occurs in these chiral bulk crystals under a charge current flowing along the principal c axis. Such phenomena are detected as an inverse spin Hall signal which is induced on the detection electrode that absorbs polarized spin from the chiral crystal. The inverse response is observed when applying the charge current into the detection electrode. The signal sign reverses in the device with the opposite chirality. Furthermore, the spin signals are found over micrometer length scales in a nonlocal configuration. Such a robust generation and protection of the spin-polarized state is discussed based on a one-dimensional model with an antisymmetric spin-orbit coupling.

We have investigated vortex structures in three-dimensional superconductors under a helical magnetic field from a chiral helimagnet numerically. In order to obtain vortex structures, we solve the three-dimensional Ginzburg–Landau equations with the finite element method. A spatial distribution of the helical magnetic field corresponds to a spatial distribution of magnetic moments in the chiral helimagnet. Then, the magnetic field is parallel to a y z -plane and helical rotation along a helical axis ( x -axis). An arrangement of the vortex is different from the spatial oscillation in each component of the magnetic field. In this calculation, two-types of vortex structures appear. One is an appearance of vortices perpendicular to a x y -plane and a z x -plane of the superconductor. The other arrangement is that vortices are tilted toward the helical axis, although the magnetic field along the helical axis is zero. The arrangement of the tilted vortex depends on a direction of a rotation in the helical magnetic field.

We examined incommensurate magnetic structures in Cr1−xMoxB2 (\(x = 0,0.15\)) by neutron diffraction experiments. Single crystals of Cr1−xMoxB2 were grown by the floating zone method. Using unpolar...

Abstarct Vortex states in a chiral helimagnet/superconductor bilayer are investigated numerically, using the Ginzburg–Landau equations with the finite element method. In this bilayer, effect of the chiral helimagnet on the superconductor is taken as an external field. Magnetic field distribution can be controlled by an applied field to the bilayer. It is shown that a single vortex in a gradient field is elongated along the field gradient. In zero applied field, there are up- and down vortices which are parallel or antiparallel to the z -axis, respectively. But increasing the applied field, down-vortices disappear and up-vortices form undulated triangular lattices.

We have performed X-band electron spin resonance (ESR) measurements on a single crystal of the metallic chiral helimagnet ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$ from 3.5 to 180 K and for the external magnetic fields ${H}_{\mathrm{ext}}$, up to 4 kOe, perpendicular to the $c$ axis (the helical axis of ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$). This field-crystalline configuration is expected to provide the chiral soliton lattice (CSL) state in this system. The main resonance line can be fit with a Dysonian function above ${T}_{\mathrm{c}}=127\phantom{\rule{0.0pt}{0ex}}\phantom{\rule{4pt}{0ex}}\mathrm{K}$, but additional features in the spectra were observed below 105 K. Specifically, spiked anomalies superposed on the main signals were observed for magnetic fields between ${H}_{\mathrm{c}1}$ and ${H}_{\mathrm{c}2}$ that are the appearing and disappearing fields of the spiked anomalies, respectively. The resulting magnetic field vs temperature phase diagram possesses three regions, which are interpreted as different dynamical responses in the CSL phase. In addition, the values of ${H}_{\mathrm{c}2}$ are close to those reported by the ${d}^{2}M/d{H}^{2}$ curve [Tsuruta et al., Phys. Rev. B 93, 104402 (2016)]. Furthermore, the field range between ${H}_{\mathrm{c}1}$ and ${H}_{\mathrm{c}2}$, where the spiked anomalies exist, depends on the field direction and shifts to higher fields when turning to the $c$ axis, thereby providing additional evidence that these spiked anomalies must be related to the chiral soliton dynamics.

We present a theory of standing spin wave (SSW) in a monoaxial chiral helimagnet. Motivated by experimental findings on the magnetic field-dependence of the resonance frequency in thin films of Cr${}$Nb$_{3} $S${}_{6}$[Goncalves et al., Phys. Rev. B95, 104415 (2017)], we examine the SSW over a chiral soliton lattice (CSL) excited by an ac magnetic field applied parallel and perpendicular to the chiral axis. For this purpose, we generalize Kittel-Pincus theories of the SSW in ferromagnetic thin films to the case of non-collinear helimagnet with the surface end spins which are softly pinned by an anisotropy field. Consequently, we found there appear two types of modes. One is a Pincus mode which is composed of a long-period Bloch wave and a short-period ripple originated from the periodic structure of the CSL. Another is a short-period Kittel ripple excited by space-periodic perturbation which exists only in the case where the ac field is applied perpendicular the chiral axis. We demonstrate that the existence of the Pincus mode and the Kittel ripple is consistent with experimentally found double resonance profile., Comment: 17 pages, 14 figures

Source differential phase contrast data showing the chiral soliton lattice dislocation magnetic configuration at low and high applied fields.

The chiral magnet ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$ with its solitonic objects has novel magnetic and transport properties, in which the spin-orbit coupling (SOC) plays a central role. Aiming to address the possible existence of orbital moments driven by SOC, we perform soft x-ray magnetic circular dichroism spectroscopy at the Cr ${L}_{2,3}$ edges with in-plane magnetization. The dichroic signals provide direct experimental evidence that the Cr orbital magnetic moment is not quenched and is coupled antiparallel to the spin counterpart. Application of the orbital sum rule reveals that the magnitude of the Cr orbital moment is about 1% of the total magnetization. These findings are consistent with the first-principles electronic structure calculations that utilize the Cr $2p$ core radial function to define the Cr local $3d$ quantities. The distinct roles of the atomic SOC among the Cr $3d$ and Nb $4d$ states are discussed.

Nonreciprocal flow of conduction electrons is systematically investigated in a monoaxial chiral helimagnet $\mathrm{C}\mathrm{r}\mathrm{N}{\mathrm{b}}_{3}{\mathrm{S}}_{6}$. We found that such directional dichroism of the electrical transport phenomena, called the electrical magnetochiral (EMC) effect, occurs in a wide range of magnetic fields and temperatures. The EMC signal turns out to be considerably enhanced below the magnetic ordering temperature, suggesting a strong influence of the chiral magnetic order on this anomalous EMC transport property. The EMC coefficients are separately evaluated in terms of crystalline and magnetic contributions in the magnetic phase diagram.

Using Lorentz transmission electron microscopy and small-angle electron scattering techniques, we investigate the temperature-dependent evolution of a magnetic stripe pattern period in thin-film lamellae of the prototype monoaxial chiral helimagnet ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$. The sinusoidal stripe pattern appears due to formation of a chiral helimagnetic order (CHM) in this material. We found that as the temperature increases, the CHM period is initially independent of temperature and then starts to shrink above the temperature of about 90 K, which is far below the magnetic phase transition temperature for the bulk material ${T}_{c}$ (123 K). The stripe order disappears at around 140 K, far above ${T}_{c}$. We argue that this cascade of transitions reflects a three-stage hierarchical behavior of melting in two dimensions.

Using cryogenic Lorentz transmission electron microscopy, we investigate the temperature evolution of magnetic structures in single crystal samples of K2CuF4 with a magnetic phase transition at 6.1...

We study effects of a chiral helimagnet (CHM) on vortex states in a superconductor, solving the Ginzburg-Landau equations in a chiral helimagnet/superconductor bilayer system. We found that vortices form a periodically modulated triangular lattice, because the magnetic field from the chiral helimagnet $H_{CHM}$ oscillates spatially. An increase of a critical current is expected, because vortices are pinned by the $H_{CHM}$., Comment: 5 pages, 7 figures, ISS2015, submitted to Physica C

Current-induced magnetization has been investigated in a monoaxial chiral crystal CrNb3S6 by means of superconducting quantum interference device magnetometry. We found that bulk magnetization was generated by applying electric current along the principal axis of the monoaxial chiral crystal and that the magnetization changed linearly with the current. Directly detecting such magnetization enables one to estimate the number of spin-polarized electrons. Using this number, we evaluated the spin polarization rate within the framework of Boltzmann's equation. We also observed that the current-induced magnetization increased in the vicinity of the phase boundary between paramagnetic and forced ferromagnetic phases, which could be attributed to the enhancement of spin fluctuation. We discuss these observations based on a chirality-induced spin selectivity effect enhanced by exchange interactions.

We investigate the magnetic field dependence of the spin excitation spectra of the chiral soliton lattice (CSL) in the helimagnet CrNb3S6, by\ud means of microwave resonance spectroscopy. The CSL is a prototype of a noncollinear spin system that forms periodically over a\ud macroscopic length scale. Following the field initialization of the CSL, we found three collective resonance modes over an exceptionally wide\ud frequency range. Upon further reducing the magnetic field toward 0 T, the spectral weight of these collective modes was disrupted by the\ud emergence of additional resonances whose Kittel-like field dependence was linked to coexisting field polarized magnetic domains. The collective behavior at a macroscopic level was only recovered upon reaching the helical magnetic state at 0 T. The magnetic history of this noncollinear spin system can be utilized to control microwave absorption, with potential use in magnon-driven devices.

We discuss how the collective magnetic resonance response of the monoaxial chiral helimagnetic crystal ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$ can be tailored by changing the area of its magnetization plane. Micrometer-sized samples of this crystal yield a number of resonance modes occurring at frequencies ranging from 15 to 20 GHz, even in the absence of a magnetic field. Changes in the resonance bandwidth, of the order of several GHz, are attributed to the effect of the spatially nonuniform demagnetization fields on standing spin wave modes. This material hosts a chiral spin soliton lattice phase, whose field robustness, degree of controllability, and the relatively unexplored polarization-dependent microwave absorption make way for novel microwave applications.

We report broadband microwave spectroscopy in micrometer-sized platelet devices of a monoaxial chiral magnetic crystal CrNb 3 S 6 with a helical c axis perpendicular to the device plane. In this device configuration, we found that the resonance of a chiral spin soliton lattice is insensitive to the direction of magnetic field H. In contrast to such behavior, resonance signals were largely suppressed in the ferromagnetic phase when the direction of H is parallel to a dominant component of the driving microwave field. Thus, by interchanging between the chiral spin soliton lattice and ferromagnetic phases, the microwave resonance can be switched on and off. The present device configuration allows us to demonstrate a switching performance, together with discrete changes in the resonance frequency by changing the H strength.

We show that the stability (existence/absence) and interaction (repulsion/attraction) of chiral solitons in monoaxial chiral magnets can be varied by tilting the direction of magnetic field. We, thereby, elucidate that the condensation of attractive chiral solitons causes the discontinuous phase transition predicted by a mean field calculation. Furthermore we theoretically demonstrate that the metastable field-polarized-state destabilizes through the surface instability, which is equivalent to the vanishing surface barrier for penetration of the solitons. We experimentally measure the magnetoresistance (MR) of micrometer-sized samples in the tilted fields in demagnetization-free configuration. We corroborate the scenario that hysteresis in MR is a sign for existence of the solitons, through agreement between our theory and experiments., 6+6 pages. the title is changed

Chiral solitons in monoaxial chiral magnets undergo a surface barrier, which is analogous to the Bean-Livingston barrier in type-II superconductors. The authors argue here that the surface barrier is the main mechanism for large hysteresis observed in magnetoresistance (MR) measurements on micrometer-sized samples of CrNb${}_{3}$S${}_{6}$. In the MR hysteresis, a conspicuous jump is observed at the field ${H}_{\mathrm{b}}$ for decreasing fields. Experimental results for ${H}_{\mathrm{b}}\ensuremath{\sim}0.4{H}_{\mathrm{c}}$ (with thermodynamic critical field ${H}_{\mathrm{c}}$) and the theoretical result ${H}_{\mathrm{b}}/{H}_{\mathrm{c}}=4/{\ensuremath{\pi}}^{2}$ are in good agreement with each other. The surface barrier is regarded as a common property of systems (superconductors, chiral magnets, and chiral liquid crystals) that exhibit continuous transitions of the nucleation type.

We investigate electrical transport properties of micrometer-sized samples of the rare-earth-based monoaxial chiral magnetic crystal ${\mathrm{YbNi}}_{3}{\mathrm{Al}}_{9}$ in order to characterize chiral magnetic structures. The magnetoresistance (MR) data exhibit discrete changes, supporting the formation of the chiral spin soliton lattice (CSL) in ${\mathrm{YbNi}}_{3}{\mathrm{Al}}_{9}$. Reversal and lock-in behavior of the MR signal are significant features during the CSL formation, which contrast with hysteresis behavior reported in a prototype monoaxial chiral magnetic crystal of ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$. The magnetic phase diagrams are provided based on the electrical transport properties in micrometer-sized ${\mathrm{YbNi}}_{3}{\mathrm{Al}}_{9}$ crystals.

A chiral soliton lattice stabilized in a monoaxial chiral magnet ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$ is a magnetic superlattice consisting of magnetic kinks with a ferromagnetic background. The magnetic kinks are considered to be topological magnetic solitons (TMSs). Changes in the TMS number yield discretized responses in magnetization and electrical conductivity, and this effect is more prominent in smaller crystals. We demonstrate that, in microprocessed ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$ crystals, TMSs are geometrically protected through element-selected micromagnetometry using soft x-ray magnetic circular dichroism (MCD). A series of x-ray MCD data is supported by mean-field and micromagnetic analyses. By designing the microcrystal geometry, TMS numbers can be successfully changed and fixed over a wide range of magnetic fields.

We have investigated vortex states in two-dimensional superconductors under a oscillating magnetic field from a chiral helimagnet. We have solved the two-dimensional Ginzburg-Landau equations with finite element method. We have found that when the magnetic field from the chiral helimagnet increases, vortices appear all at once in all periodic regions. This transition is different from that under the uniform magnetic field. Under the composite magnetic field with the oscillating and uniform fields (down-vortices), vortices antiparallel to the uniform magnetic field disappear. Then, the small uniform magnetic field easily remove down-vortices., Comment: 8 pages, 14 figures

We investigate relations between near field and far field polarization characteristics of the chiral plasmonic nanostructures, using electromagnetic simulations. We found that the spectral features of chiral near fields created by the nanostructures intercorrelate with those of far field optical rotation. This finding may provide us a method to characterize the chiral near field.

We investigate the magnetic torque and magnetoresistance (MR) responses in oblique magnetic fields in micrometer-sized specimens of the hexagonal chiral magnetic crystal ${\mathrm{CrNb}}_{3}{\mathrm{S}}_{6}$. The results exhibit hysteresis over a wide range of applied field angles, while reversible behavior appears only when the magnetic field is closely aligned to the helical axis of the crystal. Stepwise changes of the magnetic torque and MR detected in the hysteresis region indicate the existence of chiral solitons in the oblique magnetic fields. A magnetic phase diagram is derived from the experimental results, and the stability of the chiral magnetic phases, such as the chiral soliton lattice and chiral conical phase, and the nature of the phase transition between them are discussed.

The surface-enhanced chiral-optical spectroscopy is based on the interaction of chiral molecules with chiral electromagnetic near field localized on a chiral plasmonic nanostructure. It is of fundamental importance to reveal the spectral characteristics of chiral near fields for maximizing the chiral interaction. Here we investigate relations between near field and far field polarization characteristics of the chiral plasmonic nanostructures, using electromagnetic simulations. We found that spectral features of chiral near fields created by the nanostructures intercorrelate with those of far field optical rotation. This finding may provide us a method to characterize and design the chiral near field.

Amorphous titanium trisulfide (TiS3) active materials were prepared by ball milling of an equimolar mixture of crystalline titanium disulfide (TiS2) and sulfur. A high-resolution transmission electron microscope image revealed no periodic lattice fringes on the amorphous TiS3. The all-solid-state lithium secondary batteries using a sulfide solid electrolyte and the amorphous TiS3 electrode showed high capacity of greater than 300 mAh g−1 for 10 cycles. The amorphous TiS3 had a higher capacity than the mixture of crystalline TiS2 and S, which was used as the starting material of amorphous TiS3. The X-ray diffraction patterns and the Raman spectra of the amorphous TiS3 electrode after the first and tenth charge–discharge measurements were similar to those before the measurement. The amorphous structure of TiS3 did not change greatly during the first few cycles. The all-solid-state cells with the amorphous TiS3 electrode showed higher initial coulombic efficiency because the amorphous TiS3 active material retained its structure during the initial electrochemical test.

A high-angle annular-dark-field (HAADF) imaging technique was applied to the investigation of domain wall structures in the ferroelectric phase of hexagonal manganites, YMnO3, on an atomic scale. The displacements of the Y3+ ions along the [001] direction can be clearly visualized. The ferroelectric dipole moments are revealed to be caused by the opposite and unequal displacements of Y3+ ions. Two types of domain walls should be identified in the ferroelectric domain structures. One is charged longitudinal domain walls with head-to-head or tail-to-tail configurations and the other is non-charged transverse domain walls with head-to-tail configurations. In addition, the ferroelectric and the structural antiphase domains in YMnO3 change into fragmentary domains because of substitution of Ti4+ for Mn3+, and ferroelectric nanodomains with sizes of 10–20 nm are found in the x = 0.30 compound.

We have investigated vortex states in chiral helimagnet/superconductor bilayer systems under an applied external magnetic field Happl, using the Ginzburg-Landau equations. Effect of the chiral helimagnet on the superconductor is taken as a magnetic field HCHM, which is perpendicular to the superconductor and oscillates spatially. For Happl = 0 and weak HCHM, there appear pairs of up-and down-vortices. Increasing Happl, down-vortices gradually disappear, and number of up-vortices increases in the large magnetic field region. Then, up-vortices form parallel, triangular, or square structures., Comment: 7 pages, 13 figures

Under the terms of the Creative Commons Attribution license.-- et al., The zero-temperature phase diagram of the monoaxial chiral helimagnet in the magnetic-field plane formed by the components parallel and perpendicular to the helical axis is thoroughly analyzed. The nature of the transition to the commensurate state depends on the angle between the field and the helical axis. For field directions close to the directions parallel or perpendicular to the helical axis the transition is continuous, while for intermediate angles the transition is discontinuous and the incommensurate and commensurate states coexist on the transition line. The continuous and discontinuous transition lines are separated by two tricritical points with specific singular behavior. The location of the continuous and discontinuous lines and of the tricritical points depend strongly on the easy-plane anisotropy, the effect of which is analyzed. For high anisotropy the conical approximation locates the transition line very accurately, although it does not predict the continuous transitions and the tricritical behavior. It is shown that for high anisotropy, as in CrNb3S6, the form of the transition line is universal, that is, independent of the sample, and obeys a simple equation. The position of the tricritical points, which is not universal, is theoretically estimated for a sample of CrNb3S6., J.C. and V.L. acknowledge Grant No. MAT2015-68200-C2-2-P from the Spanish Ministry of Economy and Competitiveness. The work of A. S. Ovchinnikov was supported by the Government of the Russian Federation Program (02.A03.21.0006) and by the Ministry of Education and Science of the Russian Federation (Project Nos. 1437 and 2725).

In this study, quantitative reciprocal-space analyses of magnetic domain structures in magnetic artificial lattices of patterned elements were performed by means of the small-angle electron scattering (SAES) technique. Using a conventional transmission electron microscope with a LaB(6) thermal-emission electron gun, Lorentz deflection due to magnetic moments in patterned elements and Bragg diffraction due to the lattice periodicity are simultaneously recorded at an angle of the order of less than 1 10(-)(6) rad when using electron waves with high spatial coherency and large camera length. The present SAES technique together with TEM real-space imaging methods such as Lorentz microscopy will be useful in analyzing electromagnetic fields in nano-scaled materials.

Titanium sulfide thin film electrodes were prepared by the pulsed laser deposition method using a KrF excimer laser. Thin films of various compositions were prepared under several deposition conditions such as Ar gas pressure, laser fluence, and target-substrate distance. The thickness of the titanium sulfide thin film prepared under Ar gas pressure of 0.01 Pa, the pulse energy of 200 mJ/pulse, and the distance of 5 cm between the target and the substrate was ca. 400 nm. The films prepared at room temperature showed no peaks in the XRD pattern and no periodic lattice fringe in high-resolution transmission electron microscopic images, suggesting that they were amorphous. An all-solid-state cell using a TiS4.0 thin film electrode formed on a pelletized Li2S–P2S5 glass–ceramic electrolyte showed the reversible capacity of 543 mAh g−1, which was higher than that of a cell using a TiS1.7 film. The former solid-state cell retained higher capacity for 20 cycles at room temperature.