Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.

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Spintronics: Fundamentals and applications

日本物理学会誌及びJournal of the Physical Society of Japanの月刊について

http://ltl.tkk.fi/ice/Kevo/noisereview.pdf

Shot noise in mesoscopic conductors

Simple rules for the understanding of Heusler compounds

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

Nonballistic spin-field-effect transistor.

This work addresses spin-dependent magnetotransport in a band-gap-matched $\mathrm{ZnSe}/\mathrm{Zn}{}_{1\ensuremath{-}x}\mathrm{Mn}{}_{x}\mathrm{Se}$ heterostructure. In an external magnetic field the paramagnetic layer behaves as a potential well for spin-down electrons and a potential barrier for spin-up ones. My current-density calculation shows a strong suppression of the spin-up component of the current density for increasing magnetic fields; the total current density is dominated by the spin-down component for $Bg2\mathrm{T}$. This result gives rise to the possibility of devising spin filters relevant for spin-dependent optoelectronics.

Spin-Dependent Perpendicular Magnetotransport through a Tunable ZnSe/Zn 1-x Mn x Se Heterostructure: A Possible Spin Filter?

We study shot noise for spin-polarized currents and entangled electron pairs in a four-probe (beam-splitter) geometry with a local Rashba spin-orbit (s-o) interaction in the incoming leads. Within the scattering formalism we find that shot noise exhibits Rashba-induced oscillations with continuous bunching and antibunching. We show that entangled states and triplet states can be identified via their Rashba phase in noise measurements. For two-channel leads, we find an additional spin rotation due to s-o induced interband coupling which enhances spin control. We show that the s-o interaction deter-mines the Fano factor, which provides a direct way to measure the Rashba coupling constant via noise.

/pdf/rashba-spin-orbit-interaction-and-shot-noise-for-spin-2kzes3hfek.pdf

Rashba spin-orbit interaction and shot noise for spin-polarized and entangled electrons

We consider a two-channel spin transistor with weak spin-orbit induced interband coupling. We show that the coherent transfer of carriers between the coupled channels gives rise to an additional spin rotation. We calculate the corresponding spin-resolved current in a Datta–Das geometry and show that a weak interband mixing leads to enhanced spin control.

/pdf/datta-das-transistor-with-enhanced-spin-control-55u7h5g63k.pdf

Datta-Das transistor with enhanced spin control

We investigate the spin-orbit (SO) interaction in two-dimensional electron gases in quantum wells with two subbands. From the 8x8 Kane model, we derive a new intersubband-induced SO term which resembles the functional form of the Rashba SO but is nonzero even in symmetric structures. This follows from the distinct parity of the confined states (even or odd) which obliterates the need for asymmetric potentials. We self-consistently calculate the new SO coupling strength for realistic wells and find it comparable to the usual Rashba constant. Our new SO term gives rise to a nonzero ballistic spin-Hall conductivity, which changes sign as a function of the Fermi energy (epsilon(F)) and can induce an unusual Zitterbewegung with cycloidal trajectories without magnetic fields.

/pdf/spin-orbit-interaction-in-symmetric-wells-with-two-subbands-1yqr663i0x.pdf

J. Carlos Egues

Papers

Nonballistic spin-field-effect transistor.

Spin-Dependent Perpendicular Magnetotransport through a Tunable ZnSe/Zn 1-x Mn x Se Heterostructure: A Possible Spin Filter?

Rashba spin-orbit interaction and shot noise for spin-polarized and entangled electrons

Datta-Das transistor with enhanced spin control

Spin-orbit interaction in symmetric wells with two subbands.