Direction Of Dipole Research Articles

Extending Schottky–Mott rule to van der Waals heterostructures of 2D Janus materials: Influence of intrinsic dipoles

The Schottky–Mott (S–M) limit based on the S–M rule is often used to evaluate the Schottky barrier height (SBH) at metal–semiconductor (MS) van der Waals (vdW) contacts but fails at the polar interfaces. In order to extend the S–M rule to the polar interfaces, we here modify the S–M equation to predict the SBH at vdW interfaces of 2D Janus materials, taking into account the effects of intrinsic and interface dipoles. The modified S–M equation is verified based on the first-principles calculations of the MoSi2As2P2/HTaSe2F vdW interfaces, showing a sharp dependence of SBH on the dipole amplitude and direction. Specifically, n-type Schottky barriers tend to form when a semiconductor contacts with a low-work-function surface of Janus metal or a metal interfaces to the high-electron-affinity surface of Janus semiconductor; otherwise, a p-type one is preferable. Interestingly, the smallest n(p)-type SBH could be attained when both intrinsic dipole directions are the same. This work demonstrates that the S–M rule can be extended to the polar interfaces and dipole engineering is an effective strategy to tune the SBH at the MS interface.

Effects of the substituent position on the structural order, work function change, and thermopower of dichloro-substituted benzenethiolate self-assembled monolayers on Au(1 1 1)

The surface structures, electrochemical behaviors, work function changes, and thermopower of dichloro-substituted benzenethiolate self-assembled monolayers (SAMs) on gold surfaces prepared by vapor deposition were investigated using scanning tunneling microscopy (STM), cyclic voltammetry, Kelvin probe force microscopy, and thermoelectric junction measurements to understand the effects of their substituent positions. STM observations revealed that the adsorption of 2,4-dichlorobenzenethiol (2,4-DCBT) on Au(111) at 363 K for 1 h led to the formation of short-range ordered domains with a (5 × 6√7)R20° structure, while the SAMs formed at 363 K for 4 h consisted of long-range well-ordered domains with a (√3 × 5) structure. 3,4-Dichlorobenzenethiol (3,4-DCBT) SAMs showed coexistence of partial ordered domains and a disordered phase, while 3,4-DCBT SAMs showed fully disordered phases regardless of deposition time. Moreover, the Seebeck coefficient (S) increased in the order of 3,4-DCBT (4.6 ± 0.1 μV/K) < 2,4-DCBT (5.0 ± 0.4 μV/K) < 3,5-DCBT (5.2 ± 0.1 μV/K). Interestingly, the trend of S values was qualitatively consistent with that of the work function change (ΔΦ) of the SAMs. The reductive desorption behavior, work function shifts, and thermopower of aromatic thiolate SAMs were significantly modified by the structural order and direction of molecular dipoles of dichloro-substituted benzenethiols.

Stereochemically Active Lone Pair Induced Polar Tri-layered Perovskite for Record-Performance Polarized Photodetection.

Bulk photovoltaic effect, a promising optoelectronic phenomenon for generating polarized dependent steady-state photocurrent, has been widely applied in various photodetectors. However, incorporating stereochemically active lone pairs to construct bulk photovoltage in organic-inorganic hybrid perovskite (OIHP) is still elusive and challenging. Herein, bulk photovoltage (1.2 V) has been successfully achieved by introducing the stereo-chemically active lone pairs perovskitizer to construct a polar tri-layered hybrid perovskite, namely, (IBA)2MHy2Pb3Br10 (1, IBA= iso-butylamine, MHy = methylhydrazine). Strikingly, owning to the promising bulk photovoltage, 1-based detectors exhibit an ultra-highly sensitive polarized photodetection (polarization ratio of up to 24.6) under self-powered mode. This ratio surpasses all the reported 2D OIHP single-crystal photodetectors. In addition, detectors exhibit outstanding responsivity (~ 200 mA·W-1) and detectivity (~ 2.4 × 1013 Jones). More excitingly, further investigation confirms that lone pair electrons in MHy result in the separation of positive and negative charges to produce directional dipoles, which further directional alignment to generate bulk photovoltage, thereby resulting in polarization-dependent photocurrent. Our findings provide a new demonstration for polar multilayer materials' construction and may open opportunities for a host of high-sensitive polarized photodetection.

Stereochemically Active Lone Pair Induced Polar Tri‐layered Perovskite for Record‐Performance Polarized Photodetection

AbstractBulk photovoltaic effect, a promising optoelectronic phenomenon for generating polarized dependent steady‐state photocurrent, has been widely applied in various photodetectors. However, incorporating stereochemically active lone pair to construct bulk photovoltage in organic‐inorganic hybrid perovskite (OIHP) is still elusive and challenging. Herein, bulk photovoltage (1.2 V) has been successfully achieved by introducing the stereo‐chemically active lone pair perovskitizer to construct a polar tri‐layered hybrid perovskite, namely, (IBA)2MHy2Pb3Br10 (1, IBA=iso‐butylamine, MHy=methylhydrazine). Strikingly, owning to the promising bulk photovoltage, 1‐based detectors exhibit an ultra‐highly sensitive polarized photodetection (polarization ratio of up to 24.6) under self‐powered mode. This ratio surpasses all the reported two‐dimension OIHP single‐crystal photodetectors. In addition, detectors exhibit outstanding responsivity (≈200 mA W−1) and detectivity (≈2.4×1013 Jones). More excitingly, further investigation confirms that lone pair electrons in MHy+ result in the separation of positive and negative charges to produce directional dipoles, which further directional alignment to generate bulk photovoltage, thereby resulting in polarization‐dependent photocurrent. Our findings provide a new demonstration for polar multilayer materials’ construction and may open opportunities for a host of high‐sensitive polarized photodetection.

A stacked record of relative palaeointensity for past 500 ka from western equatorial Indian Ocean sediments

SUMMARY Relative palaeointensity (RPI) records can reflect the evolution of the Earth's axial dipole field and provide a suitable template for global stratigraphic correlation. Current RPI records are primarily obtained from the Atlantic and Pacific Oceans, particularly in the mid-latitudes of the Northern Hemisphere. Fewer RPI records originate from the Indian Ocean, particularly in low latitude areas, which limits sediment dating and geomagnetic evolution studies in these regions. In this study, we conduct a palaeomagnetic study on four sediment cores recovered from the western equatorial Indian Ocean (WEIO) to establish a new regional RPI stack from the past 500 ka for the global coverage of palaeointensity data, as well as a regional reference for palaeointensity-assisted stratigraphy. To estimate the RPI, the isothermal remanent magnetization is used as a normalizer. A chronological framework is constructed by correlating RPI records and environmental magnetic parameters (anhysteretic remanent magnetizationsaturation/isothermal remanent magnetization, ARM/SIRM) with PISO-1500 and LR04 δ18O curves, respectively. Our RPI stacked curve (WEIO-500) varies according to global and other regional high-resolution records. The five lows in the obtained RPI curve can be correlated with previously reported excursions. In addition, the mean inclination direction of each core is similar to the expected hypothetical geocentric axial dipole direction, with a negative inclination anomaly (mean ΔI) of −2.18° to −4.86°. The low mean ΔI and its reproducibility reflect the reliability of our chronological framework and stacked curve, thereby providing a new reference for correlating and calibrating RPI records from WEIO as well as other equatorial areas.

Dependence of photocatalytic activity on the direction of the intrinsic dipole in GaOI-based Janus structures

In Janus photocatalysts, intrinsic dipole (P) plays an important role in the separation of photogenerated carriers and photocatalytic activity for water splitting. However, effectively switching the direction of the P vector between different surfaces is still an open issue. Based on first-principles calculation, we find that the P vector relies on charge distribution, while the distribution of the conduction band maximum-distributed reduction reaction surfaces (Sc) and valence band minimum-distributed oxidation surfaces (Sv) depends on the orbital hybridization in GaOI-based Janus. The direction of the P vector can be switched between Sc and Sv by substituting a metal or halogen atomic layer. The P vector in the direction from Sc to Sv releases bandgap limitation, broadens the light absorption range, and improves high carriers’ mobility and solar-to-hydrogen efficiency (STH) efficiency, while the P vector pointing from Sv to Sc hinders the photocatalytic activity of GaOI-based Janus. Based on the investigation of STH efficiency and redox reactions, GaInOI is found to be a potential photocatalyst for overall water splitting. The stability of the Janus is studied by ab initio molecular dynamics and phonon diffusion spectrum. Current work proposes that switching the direction of the P vector between Sv and Sc is a potential route to regulate the band structure, optical absorption, and photocatalytic activity in GaOI-based Janus.

Dipole-Dependent Waveguiding in an Anisotropic Metal-Organic Framework.

The interaction between excitons and photons underlies a range of emergent technologies, such as directional light emission, molecular lasers, photonic circuits, and polaritonic devices. Two of the key parameters that impact exciton-photon coupling are the binding energy of excitons and the relative orientations between the exciton dipole and photon field. Tightly bound excitons are typically found in molecular crystals, where nevertheless the angular relationship of excitons with photon fields is difficult to control. Here, we demonstrate directional exciton dipoles and photon fields, anchored by metal-ligand coordination. In a pyrene-porphyrin bichromophoric metal-organic framework (MOF), we observe that the perpendicular arrangement of the pyrene- and porphyrin-based exciton dipoles engenders orthogonal polarizations of their respective emissions. The alignment of the directional exciton and photon fields gives rise to an anisotropic waveguide effect, where the pyrene- and the porphyrin-based emissions show distinct spatial distribution within microplate-shaped MOF crystals. This capability to simultaneously host heterogenous excitonic states and anisotropic photon fields points toward MOFs' yet-to-be-realized potential as a platform for advancing the frontier in the field of exciton-photonics, which centers around engineering emergent properties from the interplay between excitons and photons.

Large electrostrain at high temperature in bismuth sodium titanate-based piezoelectric ceramics

(1-x)[0.82Bi0.5Na0.5TiO3-0.18Bi0.5K0.5TiO3]-xAgNbO3 ceramics (abbreviated as BNKT-100xAN, x = 0–0.06) are fabricated by the solid state reaction method. It is discovered that silver niobate is completely dissolved into the lattice of 0.82Bi0.5Na0.5TiO3-0.18Bi0.5K0.5TiO3 ceramics based on characterization. The relaxation mechanism and characteristics of BNKT-100xAN ceramics are analyzed by dielectric temperature spectra and AC impedance spectra. The content of ordered domains and PNRs of BNKT-4AN ceramics is optimum, which enables it possess excellent electrostrain of 0.51%. The electrostrain almost remain constant after the 104 cycles test, suggesting that it also has great fatigue resistance. After polarization at high temperature, large electrostrain of 1.4% and inverse piezoelectric constants of 2004 pm/V are obtained at 150 °C in BNKT-4AN ceramics. The ultrahigh electrostrain is mainly promoted by the larger polarizability of the <111>-oriented and <001>-oriented defect dipoles, the same direction of defect dipoles and the spontaneous polarization direction of phase, the pinning effects of the defect dipoles on the PNRs and the collinear arrangement of the PNRs. This work indicates that lead-free piezoelectric ceramics is hopeful to be applied in piezoelectrics working at high temperature. Simultaneously, a new design paradigm also is provided for the preparation of piezoelectric ceramics with excellent performance.

Discordance of dipole asymmetries seen in recent large radio surveys with the cosmological principle

ABSTRACT In recent years, large radio surveys of active galactic nuclei, comprising millions of sources, have become available where one could investigate dipole asymmetries, assumedly arising due to a peculiar motion of the Solar system. Investigations of such dipoles have yielded in past much larger amplitudes than the cosmic microwave background (CMB) dipole, though their directions seem to lie close to the CMB dipole. Here we investigate dipole asymmetries in two recent large radio surveys, Very Large Array sky survey (VLASS) containing 1.9 million sources, covering the sky north of −40° declination, and the Rapid ASKAP Continuum Survey (RACS) containing 2.1 million sources, covering the sky south of +30° declination We find dipoles determined from the VLASS and RACS surveys to be significantly larger than the CMB dipole. Dipole directions from the VLASS and RACS data differ significantly from each other. Nevertheless, along with a number of other previously determined dipoles, including the CMB, they all appear to lie in a narrow sky region, which argues for the various dipoles to be related somehow. However, significant differences in their derived peculiar velocities, including that of the CMB, cannot be explained by a peculiar motion of the Solar system, which should necessarily be a single value. Instead, their discordant peculiar velocities may be indicating that different cosmic reference frames are moving relative to each other or that the matter distribution on cosmic scales is not homogeneous and isotropic, either scenario being in contravention of what expected from the cosmological principle.

A DFT study of electron–phonon interactions for the and defects in hexagonal boron nitride: investigating the role of the transition dipole direction

Quantum emitters in two-dimensional hexagonal boron nitride (h-BN) have generated significant interest due to observations of ultra-bright emission made at room temperature. The expectation that solid-state emitters exhibit broad zero-phonon lines at elevated temperatures has been put in question by recent observations of Fourier transform (FT) limited photons emitted from h-BN flakes at room temperature. All decoupled emitters produce photons that are directed in-plane, suggesting that the dipoles are perpendicular to the h-BN plane. Motivated by the promise of an efficient and scalable source of indistinguishable photons that can operate at room temperature, we have developed an approach using density functional theory (DFT) to determine the electron-phonon coupling for defects that have in- and out-of-plane transition dipole moments. Our DFT calculations reveal that the transition dipole for the defect is parallel to the h-BN plane, and for the defect is perpendicular to the plane. We calculate both the phonon density of states and the electron–phonon matrix elements associated with the h-BN defective structures. We find no indication that an out-of-plane transition dipole by itself will result in the low electron–phonon coupling that is expected to produce FT-limited photons at room temperature. Our work provides direction to future DFT software developments and adds to the growing list of calculations relevant to researchers in the field of solid-state quantum information processing.

Directional dipole dice enabled by anisotropic chirality

Directional radiation and scattering play an essential role in light manipulation for various applications in integrated nanophotonics, antenna and metasurface designs, quantum optics, etc. The most elemental system with this property is the class of directional dipoles, including the circular dipole, Huygens dipole, and Janus dipole. A unified realization of all three dipole types and a mechanism to freely switch among them are previously unreported, yet highly desirable for developing compact and multifunctional directional sources. Here, we theoretically and experimentally demonstrate that the synergy of chirality and anisotropy can give rise to all three directional dipoles in one structure at the same frequency under linearly polarized plane wave excitations. This mechanism enables a simple helix particle to serve as a directional dipole dice (DDD), achieving selective manipulation of optical directionality via different "faces" of the particle. We employ three "faces" of the DDD to realize face-multiplexed routing of guided waves in three orthogonal directions with the directionality determined by spin, power flow, and reactive power, respectively. This construction of the complete directionality space can enable high-dimensional control of both near-field and far-field directionality with broad applications in photonic integrated circuits, quantum information processing, and subwavelength-resolution imaging.

Dipole anisotropy in gravitational wave source distribution

Our local motion with respect to the cosmic frame of rest is believed to be dominantly responsible for the observed dipole anisotropy in the Cosmic Microwave Background Radiation (CMBR). We study the effect of this motion on the sky distribution of gravitational wave (GW) sources. We determine the resulting dipole anisotropy in GW source number counts, mass weighted number counts, which we refer to as mass intensity, and mean mass per source. The mass M dependence of the number density n(M) distribution of BBH is taken directly from the data. We also test the anisotropy in the observable mean mass per source along the direction of the CMB dipole. The current data sample is relatively small and consistent with isotropy. The number of sources required for this test is likely to become available in near future.

The MeerKAT Absorption Line Survey: Homogeneous continuum catalogues towards a measurement of the cosmic radio dipole

The number counts of homogeneous samples of radio sources are a tried and true method of probing the large-scale structure of the Universe, as most radio sources outside the Galactic plane are at cosmological distances. As such, they are expected to trace the cosmic radio dipole, an anisotropy analogous to the dipole seen in the cosmic microwave background (CMB). Results have shown that although the cosmic radio dipole matches the direction of the CMB dipole, it has a significantly larger amplitude. This unexplained result challenges our assumption of the Universe being isotropic, which can have large repercussions for the current cosmological paradigm. Though significant measurements have been made, sensitivity to the radio dipole is generally hampered by systematic effects that can cause large biases in the measurement. Here we assess these systematics with data from the MeerKAT Absorption Line Survey (MALS), a blind search for absorption lines with pointings centred on bright radio sources. With the sensitivity and field of view of MeerKAT, thousands of sources are observed in each pointing, allowing for the possibility of measuring the cosmic radio dipole given enough pointings. We present the analysis of ten MALS pointings, focusing on systematic effects that could lead to an inhomogeneous catalogue. We describe the calibration and creation of full band continuum images and catalogues, producing a combined catalogue containing 16 307 sources and covering 37.5 square degrees of sky down to a sensitivity of 10 μJy beam−1. We measure the completeness, purity, and flux recovery statistics for these catalogues using simulated data. We investigate different source populations in the catalogues by looking at flux densities and spectral indices and how they might influence source counts. Using the noise characteristics of the pointings, we find global measures that can be used to correct for the incompleteness of the catalogue, producing corrected number counts down to 100–200 μJy. We show that we can homogenise the catalogues and properly account for systematic effects. We determine that we can measure the dipole to 3σ significance with 100 MALS pointings.

Interpretation of transient electromagnetic data using zero-level curves

Geophysical data has long been used to gain insight into the geologic structure and composition of the subsurface. The geometrical characteristics of geophysical data, such as the locations of the minimum, maximum, and zero-crossings, gives insight into the subsurface based on the physics of the measured geophysical field. These characteristics provide a preliminary understanding of subsurface properties without performing expensive 3D inversions. When examining the zero-level curve (or zero-crossings) of magnetic data collected at the surface, one finds that the zero-level curve corresponds to a conic section with properties related to the location and orientation of a subsurface magnetic dipole. The zero-level curve can be inverted using a least-squares fitting to find a corresponding magnetic dipole location and direction in the subsurface. This understanding is extended in our work to time-domain electromagnetics, where current is induced and flows inside a confined conductor. The induced current creates a magnetic dipole in the subsurface conductor that can be characterized by the zero-level curve. As the current decays, the magnetic dipole in the conductor changes. At times directly after the transmitter is turned off, the direction of current flow depends primarily on the geometry of the transmitter and conductor. As time advances, the current flow tends towards the long-axis of the conductor, and the magnetic dipole aligns perpendicularly to that long axes. Inverting the zero-level curve of the electromagnetic data at every time channel of interest enables the tracking of the magnetic dipole through time, giving insight to the orientation and location of the conductor. We examine the method of interpreting zero-level curves using synthetic examples. We also apply it to field data measured over a compact volcanogenic massive sulfide deposit at the Lalor Mine site in Canada, and demonstrate that the geometrical information obtained is consistent with the results from previous studies in the area.

Theory, Design, and Verification of Miniaturized Phase-Controlled Huygens Antenna for 360° Continuous Beam Scanning

The theory, design, and verification of a novel miniaturized reconfigurable Huygens antenna with 360° continuous beam-scanning capability are demonstrated in this article. Different from the conventional Huygens topology, both the monopole-like Huygens form and the metamaterial loading technique are explored for size reduction. By creatively tuning the direction (or polarization) of the electric dipole (E-dipole) or magnetic dipole (M-dipole), a novel miniaturized pattern reconfigurable Huygens source is first proposed. Then, to control the polarization of the M-dipole [linearly polarized (LP)], a double circularly polarized (CP) wave with a tunable phase difference is introduced. Furthermore, a novel phase-controlled Huygens mechanism is developed by combining the polarization reconfigurable M-dipole and fixed E-dipole. By modulating the feeding phase of the Huygens source, the beam can be steered in any direction in the horizontal plane. The proposed theory and working principle are verified by a metamaterial-loaded tri-mode dielectric resonator radiator and a three-way phase-shifting network. The antenna is operated from 3.40 to 3.68 GHz and is capable of continuously scanning a directional beam from 0° to 360°. The realized peak gain and 3 dB beamwidth are greater than 6.3 dBi and 90°, respectively. This work proposes a new realization method for a simple, low-cost, miniaturized, vertically polarized (VP), 360° continuous beam-steering antenna. It is promising for intelligent wireless communications, the Internet-of-Things (IoT) devices, and DOA estimation applications.

Detection of Dipole Modulation in CMB Temperature Anisotropy Maps from WMAP and Planck using Artificial Intelligence

Breakdown of rotational invariance of the primordial power spectrum manifests in the statistical anisotropy of the observed Cosmic Microwave Background (CMB) radiation. Hemispherical power asymmetry in the CMB may be caused due to a dipolar modulation, indicating the presence of a preferred direction. Appropriately rescaled local variance maps of the CMB temperature anisotropy data effectively encapsulate this dipolar pattern. As a first-of-its-kind method, we train Artificial Neural Networks (ANNs) with such local variances as input features to distinguish statistically isotropic CMB maps from dipole-modulated ones. Our trained ANNs are able to predict components of the amplitude times the unit vector of the preferred direction for mixed sets of modulated and unmodulated maps, with goodness-of-fit (R 2) scores >0.97 for full sky and >0.96 for partial sky coverage. On all observed foreground-cleaned CMB maps, the ANNs detect the dipolar modulation signal with overall consistent values of amplitudes and directions. This detection is significant at 97.21%–99.38% C.L. for all full sky maps, and at 98.34%–100% C.L. for all partial sky maps. Robustness of the signal holds across full and partial skies, various foreground cleaning methods, inpainting algorithms, instruments, and all the different periods of observation for Planck and WMAP satellites. The significant and robust detection of the signal, in addition to the consistency of values of amplitude and directions, as found independent of any preexisting methods, further mitigates the criticisms of look-elsewhere effects and a posteriori inferences for the preferred dipole direction in the CMB.

Independently tunable Fano resonance from quasibound state in the continuum in hybrid graphene–dielectric metasurface for magnetic field tunability

We study an independently tunable Fano resonance from quasibound state in the continuum and polarization-independent toroidal dipole resonance in hybrid graphene–dielectric metasurface consisting of a nanoring and a cross-shaped nanobar. The unique structural properties of the proposed metasurface can support directional toroidal dipole mode, where the asymmetric magnetic field enhancement can be dynamically switched on and off while maintaining polarization-independent Fano spectral response. Through reducing or increasing inner radius of nanoring, an additional quasi-BIC dominated by magnetic dipole moment can be excited and independently tuned by altering the polarization direction of the incident wave. In addition, the quasi-BIC can be effectively modulated via adjusting the Fermi energy and layer numbers of the graphene. Our results can be of practical interest for a variety of applications including optical modulator, filter, switches, and light trapping.

Dislocation-tuned ferroelectricity and ferromagnetism of the BiFeO3/SrRuO3 interface

Misfit dislocations at a heteroepitaxial interface produce huge strain and, thus, have a significant impact on the properties of the interface. Here, we use scanning transmission electron microscopy to demonstrate a quantitative unit-cell-by-unit-cell mapping of the lattice parameters and octahedral rotations around misfit dislocations at the BiFeO3/SrRuO3 interface. We find that huge strain field is achieved near dislocations, i.e., above 5% within the first three unit cells of the core, which is typically larger than that achieved from the regular epitaxy thin-film approach, thus significantly altering the magnitude and direction of the local ferroelectric dipole in BiFeO3 and magnetic moments in SrRuO3 near the interface. The strain field and, thus, the structural distortion can be further tuned by the dislocation type. Our atomic-scale study helps us to understand the effects of dislocations in this ferroelectricity/ferromagnetism heterostructure. Such defect engineering allows us to tune the local ferroelectric and ferromagnetic order parameters and the interface electromagnetic coupling, providing new opportunities to design nanosized electronic and spintronic devices.

Scattering of light in thin magnetized envelopes – II

ABSTRACT We consider optically thin spherical stellar envelopes with dipole magnetic field. The source of magnetic dipole field is assumed point like and emits the non-polarized monochromatic radiation. This paper carry on the previous paper of authors, where the general theory is presented and the circular polarization of scattered radiation is calculated for small values of magnetic fields corresponding to parameter x ≪ 1 (x = ωB/ω ≃ 0.933 × 10−8λ(μm)B(G)). The Stokes parameters of scattered radiation mutually transform into each other due to interference. Here we obtained the explicit formulas describing the transformation of all Stokes parameters for any value of parameter x. The qualitative discussion of these formulas is presented. These formulas show that for x ∼ 1 the transformation leads to large variations of all Stokes parameters. The linear and circular polarizations acquire oscillating dependence on the propagation path. For x ≫ 1 the single scattered radiation has very small circular polarization of the order ∼1/x ≪ 1 and large linear polarization. In this case the transformation gives rise to additional value of observed circular polarization, which is proportional to initial single scattered value. The observed linear polarization acquires small inclination angle relative to the plane ‘line of sight–direction of magnetic dipole’ due to existence of small circular polarization. The Stokes parameters of single scattered radiation from all envelope without taking into account the interference effects are given for x ≫ 1.

Spin Selectivity Damage Dependence of Adsorption of dsDNA on Ferromagnets.

The adsorption of oxidatively damaged DNA onto ferromagnetic substrates was investigated. Both confocal fluorescence microscopy and quartz crystal microbalance methods show that the adsorption rate and the coverage depend on the magnetization direction of the substrate and the position of the damage site on the DNA relative to the substrate. SQUID magnetometry measurements show that the subsequent magnetic susceptibility of the DNA-coated ferromagnetic film depends on the direction of the magnetic field that was applied to the ferromagnetic film as the molecules were adsorbed. This study reveals that (i) the spin and charge polarization in DNA molecules is changed significantly by oxidative damage in the G bases and (ii) the rate of adsorption on a ferromagnet, as a function of the direction of the magnetic dipole of the surface, can be used as an assay to detect oxidative damage in the DNA.