We measured Kondo-assisted tunneling via C60 molecules in contact with ferromagnetic nickel electrodes. Kondo correlations persisted despite the presence of ferromagnetism, but peak differential conductance was split by an amount that decreased (even to zero) as moments two electrodes were turned from parallel antiparallel alignment. The splitting is too large be explained a local magnetic field. However, voltage, temperature, and field dependence signals agree predictions for exchange...

We study the Kondo effect in a quantum dot coupled to ferromagnetic leads and analyze its properties as function of spin polarization leads. Based on scaling approach, we predict that for parallel alignment magnetizations strong-coupling limit is reached at finite value magnetic field. Using an equation motion technique, nonlinear transport through dot. For alignment, zero-bias anomaly may be split even absence external antiparallel symmetric coupling, peak only presence field, but shows...

We develop a theory of electron transport through quantum dots that are weakly coupled to ferromagnetic leads. The covers both the linear and nonlinear regime, takes non-collinear magnetization leads into account, allows for an externally-applied magnetic field. derive generalized rate equations dot's occupation accumulated spin discuss influence on transmission. A negative differential conductance nontrivial dependence angle between lead magnetizations is predicted.

The Kondo effect in quantum dots (QDs)-artificial magnetic impurities-attached to ferromagnetic leads is studied with the numerical renormalization group method. It shown that QD level spin split due presence of electrodes, leading a suppression effect. We find can be restored by compensating this splitting field. Although resulting resonance then has an unusual asymmetry reduced temperature, ground state still locally screened state, describable Fermi liquid theory and generalized Friedel...

We analyze spin-dependent transport through spin valves composed of an interacting quantum dot coupled to two ferromagnetic leads. The on the and linear conductance as a function relative angle theta leads' magnetization directions is derived lowest order in dot-lead coupling strength. Because applied bias voltage accumulates dot, which for finite charging energy experiences torque, resulting precession. latter leads nontrivial, interaction-dependent, dependence conductance. In particular,...

We study electronic transport through quantum dots weakly coupled to ferromagnetic leads with collinear magnetization directions. Tunneling contributions of first and second order in the tunnel-coupling strength are taken into account. analyze tunnel magnetoresistance (TMR) for all combinations linear nonlinear response, at or off resonance, an even odd dot-electron number. Different mechanisms spin accumulation various regimes give rise different TMR behavior.

The break-junction technique is widely used to measure electronic properties of nanoscale junctions including metal point-contacts and single-molecule junctions. In these measurements, conductance measured as a function electrode displacement yielding data that analyzed by constructing histograms determine the most frequently observed values in However much rich physics measurements lost this simple analysis technique. Conductance cannot be study statistical relation distinct junction...

The effect of a gate voltage ($V_g$) on the spin-splitting an electronic level in quantum dot (QD) attached to ferromagnetic leads is studied Kondo regime using generalized numerical renormalization group technique. We find that $V_g$-dependence QD strongly depends shape density states (DOS). For one class DOS shapes there nearly no $V_g$-dependence, for another, $V_g$ can be used control magnitude and sign spin-splitting, which interpreted as local exchange magnetic field. acquires new type...

Scanning thermal microscopy is a unique tool for the study of properties at nanoscale. However, calibration method crucial problem. When analyzing local conductivity, direct not possible and reference samples are used instead. As dependence non-linear there only few points, this represents metrological challenge that needs complex data processing. In contribution we present use OEFPIL algorithm robust single-step evaluation conductivities their uncertainties, simplifying procedure....

We study the Kondo effect in electron transport through a quantum dot coupled to ferromagnetic leads, using real-time diagrammatic technique which provides systematic description of nonequilibrium dynamics system with strong local correlations. evaluate theory an extension `resonant tunneling approximation', introduced earlier, by introducing self-energy off-diagonal component reduced propagator spin space. In this way we develop charge and conserving approximation that accounts not only for...

We systematically study the influence of ferromagnetic leads on Kondo resonance in a quantum dot tuned to local moment regime. employ Wilson's numerical renormalization group method, extended handle with spin asymmetric density states, identify effects (i) finite polarization (at Fermi surface), (ii) Stoner splitting bands (governed by band edges), and (iii) an arbitrary shape lead states. For generic favors being occupied particular species due exchange interaction leads, leading...

We study frequency-dependent current noise through a single-level quantum dot connected to ferromagnetic leads with non-collinear magnetization. propose use the Fano factor as tool detect single-spin dynamics in dot. Spin precession due an external magnetic and/or many-body exchange field affects of system two ways. First, tendency towards spin-selective bunching transmitted electrons is suppressed, which gives rise reduction low-frequency noise. Second, spectrum displays resonance at Larmor...

We investigate theoretically the use of nonideal ferromagnetic contacts as a means to detect quantum entanglement electron spins in transport experiments. designated witness and find minimal spin polarization $\ensuremath{\eta}>1/\sqrt{3}\ensuremath{\approx}58%$ required demonstrate entanglement. This is significantly less stringent than ubiquitous tests Bell's inequality with $\ensuremath{\eta}>1/\sqrt[4]{2}\ensuremath{\approx}84%$. In addition, we discuss impact decoherence noise on...

We predict a new zero-bias anomaly in the differential conductance through quantum dot coupled to two ferromagnetic leads with antiparallel magnetization. The differs origin and properties from other anomalies transport dots, such as Kondo effect. It occurs Coulomb-blockade valleys an unpaired electron. is consequence of interplay single- double-barrier cotunneling processes their effect on spin accumulation dot. becomes significantly modified when magnetic field applied.

We present a novel statistical method for the study of stable atomic configurations in breaking nanowires based on 2D cross-correlation analysis conductance versus electrode separation traces. Applying this method, we can clearly resolve typical evolutions staircase some transition metal nanojunctions (Ni, Fe, V) up to high values. In these metals our demonstrates very well ordered narrowing nanowire, indicating regular, stepwise decrease number atoms minimal cross section junction, contrast...

We investigate the effects induced by ferromagnetic contacts attached to a serial double quantum dot. Spin polarization generates effective magnetic fields and suppresses Kondo effect in each The superexchange interaction ${J}_{\mathrm{AFM}}$, tuned interdot tunneling rate $t$, can be used compensate restore resonance when contact polarizations are aligned. As consequence, direction of spin conductance controlled even reversed using electrostatic gates alone. Our results demonstrate new...

Frequency dependent current noise in ferromagnetic double junctions with Coulomb blockade is studied theoretically the limit of sequential tunneling. Two different relaxation processes are found correlations between spin polarized tunneling currents; low frequency fluctuations and high charge fluctuations. Spin accumulation strongly asymmetric shown to lead a negative differential resistance. We also show that large activated range resistance gives rise significant enhancement noise.

Electron tunneling in ferromagnetic single-electron transistors is considered theoretically the sequential regime. A new formalism developed, which operates a two-dimensional space of states, instead one-dimensiona used spinless case. It shown that spin fluctuations can be significantly larger than charge fluctuations. The influence discrete energy spectrum small central electrode on current, and accumulation, fluctuations, tunnel magnetoresistance analyzed details. Two different scales are...

We present a large area high-speed measuring system capable of rapidly generating nanometre resolution scanning probe microscopy data over mm2 regions. The combines slow moving but accurate XYZ scanner with very fast less small XY scanner. This arrangement enables areas to be scanned by stitching together the small, acquired, images from while simultaneously across region interest. In order successfully merge image sequences two software approaches for calibrating are described. first...

A Josephson current through a half-metallic ferromagnet between two conventional superconductors is theoretically studied. The spin dynamics such as magnon excitation plays crucial role not only for the conversion spin-singlet and spin-triplet pairs but also formation of composite state triplet Cooper pair magnon, by which flows superconductors. We propose supercurrent pumping driven coherent precession magnetization tuning microwave frequency to ferromagnetic resonance in junction.

We analyze a model of double quantum dot Cooper pair splitter coupled to two ferromagnetic detectors and demonstrate the possibility determination spin correlation by current measurements. use perturbation theory, taking account exchange interaction with detectors, which leads complex dynamics in dots. This affects measured restricts nonlinear current-voltage characteristic regime at plateau, where relevant projection is conserved, contrast linear regime, information distorted. Moreover, we...

We propose a method of direct detection spin accumulation, which overcomes problems previous measurement schemes. A spin-dependent current in single-electron transistor with ferromagnetic electrodes leads to accumulation on the metallic island. The resulting splitting electrochemical potentials island, because an additional shift by charging energy, can be detected from spacing between two resonances current-voltage characteristics. results were obtained framework real-time diagrammatic...

We discuss a device---a purely capacitively coupled interacting triple quantum dot system in an external magnetic field---for the observation of SU(3) Kondo effect, identified by conductance being pinned to characteristic value $3/4$ unitary limit. The effect occurs two plateaus where occupancy is integer value, either 1 or 2. thermodynamic and spectral properties corresponding triple-impurity model establish how presence screening can be temperature dependence through one dots. report...

We suggest a series of transport experiments on spin precession in quantum dots coupled to one or two ferromagnetic leads. Dot states are created by injection and analyzed via the linear conductance through dot, while an applied magnetic field gives rise Hanle effect. Such experiment can be used determine lifetime measure efficiency into as well proving existence intrinsic which is driven Coulomb interaction.