Abstract Thin-film sub-5 nm magnetic skyrmions constitute an ultimate scaling alternative for future digital data storage. Skyrmions are robust noncollinear spin textures that can be moved and manipulated by small electrical currents. Here we show here a technique to detect isolated nanoskyrmions with current perpendicular-to-plane geometry, which has immediate implications device concepts. We explore the physics behind such mechanism studying atomistic electronic structure of...

We demonstrate using inelastic scanning tunneling spectroscopy and simulations based on density functional theory that the amplitude sign of magnetic anisotropy energy for a single Fe atom adsorbed onto Pt(111) surface can be manipulated by modifying adatom binding site. Since magnitude measured is remarkably small, up to an order smaller than previously reported, electron-hole excitations are weak thus spin excitation exhibits long lived precessional lifetimes compared values found same...

Abstract Chiral magnets are a promising route towards dense magnetic storage technology due to their inherent nano-scale dimensions and energy efficient properties. Engineering chiral requires atomic-level control of the exchange interactions, including Dzyaloshinskii–Moriya interaction, which defines rotational sense for magnetization two coupled moments. Here we show that indirect conduction electron-mediated interaction between individual atoms on metallic surface can be manipulated by...

When electrons are driven through unconventional magnetic structures, such as skyrmions, they experience emergent electromagnetic fields that originate several Hall effects. Independently, ground-state can also lead to orbital magnetism, even without the spin-orbit interaction. The close parallel between geometric theories of effects and magnetization raises question: does a skyrmion display topological magnetism? Here we first address smallest systems with nonvanishing field, trimers,...

Whether rare-earth materials can be used as single-atom magnetic memory is an ongoing debate in recent literature. Here we show, by inelastic and spin-resolved scanning tunnelling-based methods, that observe a strong signal excitation from Fe atoms adsorbed on Pt(111), but see no signatures of or spin-based telegraph noise for Ho atoms. Moreover, the indirect exchange field produced single atom negligible, sensed nearby We demonstrate, using ab initio this stems comparatively weak coupling...

We compare three distinct computational approaches based on first-principles calculations within density functional theory to explore the magnetic exchange and Dzyaloshinskii-Moriya interactions (DMI) of a Co monolayer Pt(111), namely (i) method infinitesimal rotations moments Korringa-Kohn-Rostoker (KKR) Green function method, (ii) generalized Bloch theorem applied spiraling structures (iii) supercell with non-collinear moments, latter two being full-potential linearized augmented plane...

The structural phase transitions and the fundamental band gaps of ${\text{Mg}}_{x}{\text{Zn}}_{1\ensuremath{-}x}\text{O}$ alloys are investigated by detailed first-principles calculations in entire range Mg concentrations $x$, applying a multiple-scattering theoretical approach (Korringa-Kohn-Rostoker method). Disordered treated within coherent-potential approximation. for various crystal phases have given rise to diagram good agreement with experiments other approaches. transition from...

We present a theoretical study of the binding energy an exciton in cylindrical quantum well wire subject to external magnetic field. Calculations are performed using variational approach within effective mass approximation. describe effect confinement by infinitely deep potential taking into consideration interaction between charge carriers (electron and hole) optical phonons. It is shown that polaronic correction important should not be neglected. The introduced field, addition geometrical...

We present measurements of the effective electron mass in biaxial tensile strained silicon on insulator (SSOI) material with 1.2 GPa stress and unstrained SOI. Hall-bar metal oxide semiconductor field effect transistors 60 nm SSOI SOI were fabricated Shubnikov–de Haas oscillations temperature range T=0.4–4 K for magnetic fields B=0–10 T measured. The samples was determined as mt=(0.20±0.01)m0. This result is excellent agreement first-principles calculations presence strain.

We have studied the polaron effect on binding energy of shallow hydrogenic impurities in a cylindrical quantum dot using variational approach for finite confinement potential. The interactions charge carriers (electron and ion) with both confined LO phonon surface phonons (SSO TSO) are taken into account. these three modes donor is examined. emphasis placed dependence polaronic corrections size. It found that correction due to more important than optical modes.

Abstract The viability of past, current and future devices for information technology hinges on their sensitivity to the presence impurities. latter can reshape extrinsic Hall effects or efficiency magnetoresistance effects, essential spintronics, lead resistivity anomalies, so-called Kondo effect. Here, we demonstrate that atomic defects enable highly efficient all-electrical detection spin-swirling textures, in particular magnetic skyrmions, which are promising bit candidates spintronics...

The nature of the weakly dispersive electronic band near Fermi level observed in photoemission experiments on diluted magnetic semiconductor GaMnAs is investigated theoretically. combination experimental features appears puzzling. We show that formation closely related to presence Mn interstitial impurities. states forming have predominantly minority-spin Mn-3d character. low intensity explained by content are robust with respect calculational technique [local density approximation (LDA), LDA + U].

Abstract The structural and electronic properties of strained silicon are investigated quantitatively with ab initio computational methods. For this purpose we combine densityfunctional theory within the local‐density approximation GW for self‐energy. From variation total energy as a function applied strain obtain elastic constants, Poisson ratios related parameters, taking possible internal relaxation fully into account. biaxial tensile in (001) (111) planes then investigate effects on band...

Magnetic skyrmions are spin swirling solitonic defects that can play a major role in information technology. Their future applications and devices hinges on their efficient manipulation detection. Here, we explore from ab-initio nature as magnetic inhomongeities an otherwise unperturbed material, Fe layer covered by thin Pd film deposited top of Ir(111) surface. The presence triggers scattering processes, which Friedel oscillations emerge. latter mediate interactions among or between other...

This study analyzes the role of magnetic field and polaron effect on binding energy shallow donor impurities in a cylindrical quantum dot (QD), where is applied axial direction. The interactions carrier charges (electron ion) with confined longitudinal optical phonons as well side surface top are considered. Calculations made using effective-mass approximation within variational approach for an infinite confinement potential at all surfaces system. Results obtained function sizes (radius...

The influence of the interaction between a charge carrier (electron and ion) optical phonons (confined LO, TSO SSO) on binding energy shallow donors is investigated. effect quantum confinement described by an infinitely deep potential well. Our numerical results show that LO-phonon more important than (SSO)-phonon effects. In addition, exchange electron fixed positive via affects considerably impurities.

Abstract We present a systematic first-principles study of the electronic surface states and resonances occuring in thin films Pd various thicknesses deposited on single ferromagnetic monolayer (ML) Fe top Ir(111) substrate. This system is interest since one layer Fe/Ir(111) hosts small magnetic skyrmions. The latter are topological objects with swirling spin-textures possible implications context spintronic devices they have potential to be used as bits for information technology....

This article presents a theoretical analysis of the dependence exciton binding energy and exciton–LO-phonon coupling on cylindrical quantum dot (QD) size. The effect temperature integrated photoluminescence line intensity is also investigated. Calculations were performed within effective-mass approximation by using variational method. Specific applications these results are given for CdTe QDs embedded in Cd1−xZnxTe matrix. excitonic confinement described finite, deep potential well. We...