We propose a spin-field-effect transistor based on spin-orbit coupling of both the Rashba and Dresselhaus types. Different from earlier proposals, spin transport through our device is tolerant against spin-independent scattering processes. Hence requirement strictly ballistic can be relaxed. This follows unique interplay between coupling; these tuned to have equal strengths, leading k-independent eigenspinors even in two dimensions. discuss two-dimensional devices as well quantum wires. In...

We characterize and classify quantum correlations in two-fermion systems having 2K single-particle states. For pure states we introduce the Slater decomposition rank (in analogy to Schmidt rank), i.e. decompose state into a combination of elementary determinants formed by mutually orthogonal Mixed can be characterized their number which is minimal required generate them. K=2 give necessary sufficient condition for have 1. correlation measure mixed evaluated analytically K=2. higher K,...

Quantum gates that temporarily increase singlet-triplet splitting in order to swap electronic spins coupled quantum dots, lead inevitably a finite double-occupancy probability for both dots. By solving the time-dependent Schr\"odinger equation dot model, we demonstrate this does not necessarily computation errors. Instead, ground state evolves quasi-adiabatically typical system parameters so at completion of swapping is negligibly small. We introduce measure entanglement which explicitly...

We study the zitterbewegung of electronic wave packets in III-V zinc-blende semiconductor quantum wells due to spin-orbit coupling. Our results suggest a direct experimental proof this fundamental effect, confirming long-standing theoretical prediction. For electron motion harmonic wire, we numerically and analytically find resonance condition maximizing zitterbewegung.

In a two-dimensional electron gas as realized by semiconductor quantum well, the presence of spin-orbit coupling both Rashba and Dresselhaus type leads to anisotropic dispersion relations Fermi contours. We study effect this anisotropy on electrical conductivity in fixed impurity scatterers. The also shows general an which can be tuned varying coefficient. This provides method detecting investigating measuring spin-unpolarized currents diffusive regime. Our approach is based exact solution...

Graphene’s high mobility and Fermi velocity, combined with its constant light absorption in the visible to far-infrared range, make it an ideal material fabricate high-speed ultrabroadband photodetectors. However, precise mechanism of photodetection is still debated. Here, we report wavelength polarization-dependent measurements metal–graphene–metal This allows us quantify control relative contributions both photothermo- photoelectric effects, adding overall photoresponse. paves way for a...

Spintronics continues to be a field of fast evolution where new concepts and devices are continuously being developed. One the limiting factors in spintronics is decoherence time materials used. This Colloquium reviews current situation understanding some important semiconductors which considered applications.

We investigate the dynamical dielectric function of a monolayer molybdenum disulfide within random phase approximation. While in graphene damping plasmons is caused by interband transitions, due to large direct band gap MoS${}_{2}$ collective charge excitations enter intraband electron hole continuum similarly situation two-dimensional and gases. Since there no electron-hole symmetry MoS${}_{2}$, plasmon energies $p$- $n$-doped samples clearly differ. The breaking spin degeneracy intrinsic...

We investigate the spin-Hall effect of both electrons and holes in semiconductors using Kubo formula correct zero-frequency limit taking into account finite momentum relaxation time carriers real semiconductors. This approach allows us to analyze range validity recent theoretical findings. In particular, conductivity vanishes for vanishing spin-orbit coupling if is performed.

We review and summarize recent theoretical experimental work on electron spin dynamics in quantum dots related nanostructures due to hyperfine interaction with surrounding nuclear spins. This topic is of particular interest respect several proposals for information processing solid state systems. Specifically, we investigate the an confined a dot s-type conduction band spins dot. proportional square modulus wavefunction at location each nucleus leading inhomogeneous coupling, i.e. nuclei...

We investigate spin transport of heavy holes in III-V semiconductor quantum wells the presence spin-orbit coupling Rashba type due to structure-inversion asymmetry. Similarly case electrons, longitudinal conductivity vanishes, whereas off-diagonal elements spin-conductivity tensor are finite giving rise an intrinsic spin-Hall effect. For a clean system we find closed expression for depending on length scale and hole density. In this limit is enhanced compared its value electron systems, it...

We investigate the spin-orbit (SO) interaction in two-dimensional electron gases quantum wells with two subbands. From 8x8 Kane model, we derive a new intersubband-induced SO term which resembles functional form of Rashba but is nonzero even symmetric structures. This follows from distinct parity confined states (even or odd) obliterates need for asymmetric potentials. self-consistently calculate coupling strength realistic and find it comparable to usual constant. Our gives rise ballistic...

We investigate the minimum conductivity of graphene within a quasiclassical approach taking into account electron-hole coherence effects which stem from chiral nature low energy excitations. Relying on an analytical solution kinetic equation in coherent and incoherent cases, we study both electrical thermal whose relation satisfies Wiedemann-Franz law. find that most previous findings based Boltzmann are restricted to only high mobility samples where not sufficient.

We have developed a Hartree-Fock theory for electrons on honeycomb lattice aiming to solve long-standing problem of the Fermi velocity renormalization in graphene. Our model employs no fitting parameters (like an unknown band cutoff) but relies topological invariant (crystal structure function) that makes sublattice spinor independent electron-electron interaction. Agreement with experimental data is obtained assuming static self-screening including local field effects. As application model,...

We study the time evolution of a single spin coupled inhomogeneously to environment. Such system is realized by electron bound in semiconductor nanostructure and interacting with surrounding nuclear spins. find striking dependencies on type initial state system. Simple product states show profoundly different behavior than randomly correlated whose provides an illustrative example quantum parallelism entanglement decoherence phenomenon.

We report on Monte Carlo studies of the kinetic exchange model for (III,Mn)V ferromagnetic semiconductors in which $S=5/2$ local moments, representing ${\mathrm{Mn}}^{2+}$ ions, are coupled to band electrons. treat spin orientations as classical degrees freedom and use hybrid algorithm explore thermodynamically important $\mathrm{Mn}$ configurations. The critical temperature ${T}_{c}$ is unambiguously signalled our finite-size simulations by pronounced peaks fluctuations both carrier total...

We investigate the magnetoelectric (or inverse spin-galvanic) effect in two-dimensional electron gases with both Rashba and Dresselhaus spin-orbit couplings using an exact solution of Boltzmann equation for spin momentum. The response to in-plane electric field turns out be highly anisotropic, while usual charge conductivity remains isotropic, contrary earlier statements.

The notion of zitterbewegung is a long-standing prediction relativistic quantum mechanics. Here we extend earlier theoretical studies on this phenomenon for the case III--V zinc-blende semiconductors which exhibit particularly strong spin-orbit coupling. This property makes nanostructures made these materials very favorable systems possible experimental observations zitterbewegung. Our investigations include electrons in $n$-doped wells under influence both Rashba and Dresselhaus...

The intrinsic spin Hall effect in semiconductors has developed to a remarkably lively and rapidly growing branch of research the field semiconductor spintronics. In this article we give pedagogical overview on both theoretical experimental accomplishments challenges. Emphasis is put description mechanisms transport III-V zinc-blende semiconductors, effects dissipation.

We study the entanglement spectrum of spin-$1/2$ $XXZ$ ladders both analytically and numerically. Our analytical approach is based on perturbation theory starting either from limit strong rung coupling, or opposite case dominant coupling along legs. In former we find to leading order that Hamiltonian also nearest-neighbor form although with an, in general, renormalized anisotropy. For cases $XX$ isotropic Heisenberg no such renormalization takes place. second-order correction consists a plus...

We study the photoinduced manipulation of charge carriers in monolayer silicene subject to intense electromagnetic terahertz radiation. Considering Dirac cone approximation and going beyond off-resonant condition for large frequencies radiation field, where only virtual photon processes are allowed, we present exact zero-momentum pseudospin polarization numerical results quasienergy band structure time-averaged density states. find that resonant processes, due real emission absorbtion induce...

Abstract We introduce an effective tight-binding model to discuss penta-graphene and present analytical solution. This only involves the π -orbitals of sp 2 -hybridized carbon atoms reproduces two highest valence bands. By introducing energy-dependent hopping elements, originating from elimination 3 atoms, also lowest conduction bands can be well approximated - but after inclusion a Hubbard onsite interaction as assisted terms. The eigenfunctions analytically for without elements optical...

At small layer separations, the ground state of a nu = 1 bilayer quantum Hall system exhibits spontaneous interlayer phase coherence. The evolution this with increasing separation d has been matter controversy. We report on exact diagonalization calculations which suggest that single-phase transition, likely first order, separates incompressible states strong correlations from compressible weak correlations. find dependence boundary and tunneling amplitude is in very good agreement recent...

Anisotropic magnetoresistance (AMR) is a relativistic magnetotransport phenomenon arising from combined effects of spin-orbit coupling and broken symmetry ferromagnetically ordered state the system. In this work we focus on one realization AMR in which enters via specific spin-textures carrier Fermi surfaces ferromagnetism elastic scattering carriers polarized magnetic impurities. We report detailed heuristic examination, using model coupled systems, emergence positive (maximum resistivity...