Search arXivSearch

arXiv · 1406.1434

Electric control of spin injection into a ferroelectric semiconductor

Abstract

Electric-field control of spin-dependent properties has become one of the most attractive phenomena in modern materials research due the promise of new device functionalities. One of the paradigms in this approach is to electrically toggle the spin polarization of carriers injected into a semiconductor using ferroelectric polarization as a control parameter. Using first-principles density functional calculations, we explore the effect of ferroelectric polarization of electron-doped BaTiO3 (n-BaTiO3) on the spin-polarized transmission across the SrRuO3/n-BaTiO3 (001) interface. Our study reveals that the interface transmission is negatively spin-polarized and that ferroelectric polarization reversal leads to a change in the transport spin polarization from -65% to -98%. We show that this effect stems from the large difference in Fermi wave vectors between up- and down-spins in ferromagnetic SrRuO3 and a change in the transport regime driven by ferroelectric polarization switching. The predicted sizeable change in the spin polarization provides a non-volatile mechanism to electrically control spin injection in semiconductor-based spintronics devices.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Xiaohui Liu, J. D. Burton, Evgeny Y. Tsymbal. 2014-06-05. Electric control of spin injection into a ferroelectric semiconductor. https://doi.org/10.1103/physrevlett.114.046601

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Structure and dynamics of the negative thermal expansion material Cd(CN)$_2$ under hydrostatic pressure

We use a combination of variable-temperature / variable-pressure neutron powder diffraction, variable-pressure inelastic neutron scattering, and quantum chemical calculations to interrogate the behaviour of the negative thermal expansion (NTE) material $^{114}$Cd(CN)$_2$ under hydrostatic pressure. We determine the equation of state of the ambient-pressure phase, and discover the so-called `warm hardening' effect whereby the material becomes elastically stiffer as it is heated. We also identify a number of high-pressure phases, and map out the phase behaviour of Cd(CN)$_2$ over the range $0\leq p\leq0.5$\,GPa, $100\leq T\leq300$\,K. As expected for an NTE material, the low-energy phonon frequencies are found to soften under pressure, and we determine an effective Gr{ü}neisen parameter for these modes. Finally, we show that the elastic behaviour of Cd(CN)$_2$ is sensitive to the local Cd coordination environment, which suggests an interplay between short- (phononic) and long-timescale (cyanide flips) fluctuations in Cd(CN)$_2$.

cond-mat.mtrl-sci

Unconventional Magnetism, Sliding Ferroelectricity, and Magneto-Optical Kerr Effect in Multiferroic Bilayers

Antiferromagnetic (AFM) materials provide a platform to couple altermagnetic (AM) spin-splitting with the magneto-optical Kerr effect (MOKE), offering potential for next-generation quantum technologies. In this work, first-principles calculations, symmetry analysis, and kp modeling are employed to show that interlayer sliding in AFM multiferroic bilayers enables control of electronic, magnetic, and magneto-optical properties. This study reveals an intriguing dimension-driven AM crossover: the 2D paraelectric (PE) bilayer exhibits spin-degenerate bands protected by the [C2||Mc] spin-space symmetry, whereas the 3D counterpart manifests AM spin-splitting along kz \neq 0 paths. Furthermore, interlayer sliding breaks this Mc symmetry and stabilizes a ferroelectric (FE) state with compensated ferrimagnetism, where the Zeeman-like field is responsible for the nonrelativistic spin-splitting. In the FE phase, spin-orbit coupling (SOC) lifts accidental degeneracies and produces `alternating' spin-polarized bands through the interplay of Zeeman and Rashba effects. Crucially, spin polarization, ferrovalley polarization, and the Kerr angle can all be reversed by switching either sliding ferroelectricity or the Neel vector. Our findings reveal the rich coupling among electronic, magnetic, and optical orders in sliding multiferroics, illustrating new prospects for ultralow-power spintronic and optoelectronic devices.

cond-mat.mtrl-sci

Lead-free piezoelectric perovskites for arterial-pulse e-skin: from configurational complexity to equivariant machine-learning potentials

Continuous, non-invasive monitoring of the arterial pulse is a clinical priority for cardiovascular disease, the leading cause of global mortality. Flexible piezoelectric electronic skins can transduce the 1-10 kPa pressure wave into a self-powered voltage, but the best-performing piezoceramics are lead-based, and their toxicity is incompatible with skin contact and with tightening RoHS/REACH regulation. Among lead-free alternatives, the BaTiO$3$-based solid solution BZT-BCT reaches $d{33} \approx 620$ pC/N near its tricritical morphotropic phase boundary, rivalling soft PZT while remaining biocompatible. Exploiting this in a wearable confronts a sensitivity-flexibility paradox and three computational walls: the combinatorial explosion of atomic configurations in a disordered solid solution, the band-gap error of affordable density-functional approximations, which corrupts leakage and insulation estimates, and the 0 K nature of standard calculations against a 310 K operating temperature. We review lead-free piezoelectrics, morphotropic-boundary physics and fabricated flexible devices, then argue that equivariant machine-learning interatomic potentials --- coupled to a tiered functional hierarchy and finite-temperature lattice dynamics --- can survey the full configurational ensemble at body temperature and close the gap to a clinically viable lead-free pulse sensor.

cond-mat.mtrl-sci