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Two-dimensional (2D) crystals offer a unique platform due to their remarkable and contrasting spintronic properties, such as weak spin–orbit coupling (SOC) in graphene and strong SOC in molybdenum disulfide (MoS2). Here we combine graphene and MoS2 in a van der Waals heterostructure (vdWh) to demonstrate the electric gate control of the spin current and spin lifetime at room temperature. By performing non-local spin valve and Hanle measurements, we unambiguously prove the gate tunability of the spin current and spin lifetime in graphene/MoS2 vdWhs at 300 K. This unprecedented control over the spin parameters by orders of magnitude stems from the gate tuning of the Schottky barrier at the MoS2/graphene interface and MoS2 channel conductivity leading to spin dephasing in high-SOC material. Our findings demonstrate an all-electrical spintronic device at room temperature with the creation, transport and control of the spin in 2D materials heterostructures, which can be key building blocks in future device architectures., Two-dimensional materials are unique to build heterostructures with contrasting spintronic properties. Here, Dankert and Dash utilize a van der Waals heterostructure with graphene and MoS2 to demonstrate an all-electrical device for creation, transport and control of the spin current up to room temperature.

Semiconductors with strong spin–orbit interaction as the underlying mechanism for the generation of spin-polarized electrons are showing potential for applications in spintronic devices. Unveiling the full spin texture in momentum space for such materials and its relation to the microscopic structure of the electronic wave functions is experimentally challenging and yet essential for exploiting spin–orbit effects for spin manipulation. Here we employ a state-of-the-art photoelectron momentum microscope with a multichannel spin filter to directly image the spin texture of the layered polar semiconductor BiTeI within the full two-dimensional momentum plane. Our experimental results, supported by relativistic ab initio calculations, demonstrate that the valence and conduction band electrons in BiTeI have spin textures of opposite chirality and of pronounced orbital dependence beyond the standard Rashba model, the latter giving rise to strong optical selection-rule effects on the photoelectron spin polarization. These observations open avenues for spin-texture manipulation by atomic-layer and charge carrier control in polar semiconductors., This work was supported by DFG (through SFB 1170 ‘ToCoTronics’) and through FOR1162 (P3). We acknowledge the support by the Basque Departamento de Educacion, UPV/EHU (Grant Number IT-756-13), Spanish Ministerio de Economia y Competitividad (MINECO Grant Number FIS2013-48286-C2-2-P), Tomsk State University Academic D.I. Mendeleev Fund Program in 2015 (Research Grant Number 8.1.05.2015), the Russian Foundation for Basic Research (Grant Numbers 15-02-01797 and 15-02-589 02717). Partial support by the Saint Petersburg State University (Grant Number 15.61.202.2015) is also acknowledged.

We report a Rashba spin splitting of a two-dimensional electron gas in the topological insulator Bi2Se3 from angle-resolved photoemission spectroscopy. We further demonstrate its electrostatic control, and show that spin splittings can be achieved which are at least an order-of-magnitude larger than in other semiconductors. Together these results show promise for the miniaturization of spintronic devices to the nanoscale and their operation at room temperature. Publisher PDF

In this paper, we report on field-effect experiments in ${\text{La}}_{0.7}{\text{Sr}}_{0.3}{\text{MnO}}_{3}$ side-gate channels patterned on ultrathin epitaxial films having thickness ranging from 12 to 4 unit cells. Transport mechanisms and competition between phases, under the effect of electric and magnetic fields, as well as of other perturbations such as disorder and proximity to the interface with substrate are explored. We observe, in a 7 unit cells thick sample, a shift of the metal-insulator transition temperature as high as 43 K and a resistivity modulation up to 250% at low temperatures. In striking contrast, the 6--4 unit cells thick samples result to be insulating and almost insensitive to field-effect modulation. Such a finding indicates that for films thinner than 7 unit cells, a strong localization mechanism develops, which cannot be healed by band refilling. On the other hand, our results are compatible with a Mn ${e}_{g}$ orbital rearrangement driven by the broken translational symmetry at the surface and/or interface, which suppresses the double-exchange mechanism and localizes the carriers.

The original publication is available at www.springerlink.com http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TXG-4D9DFG8-1&_user=884697&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000047341&_version=1&_urlVersion=0&_userid=884697&md5=82925c8b0d6d8e4037c2d52c5965cafa; International audience; In this work, we present the modification of above structures with a thin layer of p-tert-butyl-calix[6]arene deposited by spin-coating process. Capacitance and impedance measurements show that this sensitive thin films can he used to nickel detection. It is shown that developed chemical sensors with silicon nitride insulating substrate exhibit good stability due to the excellent adhesion of the film, high sensitivity and good selectivity. These interesting performances could not be achieved in the case of spin-coated p-tert-butyl-calix[6]arene thin layer on Si/SiO2 heterostructure treated in the same conditions. The results were simulated by an extended site binding model which carry out that the sensitivity of the sensor is due to electrochemical phenomena between the functionalized surface and the ions of the m he electrolyte. To analyze electrochemical impedance spectroscopy results and determine fundamental physical processes which govern the response of the system, an electrical equivalent circuit is proposed.

Gate control and amplification of magnetoresistance are demonstrated at room temperature in a fully epitaxial three-terminal GaAs-based device. In addition to the two ferromagnetic spin injector and detector electrodes of a MnAs/AlAs/GaAs:Mn/AlAs/MnAs vertical spin valve, a third non-magnetic gate electrode (Ti/Au) is placed directly on top of the heavily p-doped GaAs channel layer. The magnetoresistance of the device can be amplified to reach values as high as 500% at room temperature with the application of a bias to the gate terminal, which modulates the spin selectivity of the tunnel barriers. The experimental results are modeled by solving spin drift-diffusion and tunneling equations self consistently. (C) 2011 American Institute of Physics. [doi:10.1063/13652765]

(Ga, Mn)As and other diluted magnetic semiconductors (DMS) attract a great deal of attention for potential spintronic applications because of the possibility of controlling the magnetic properties via electrical gating. Integration of a ferroelectric gate on the DMS channel adds to the system a non-volatile memory functionality and permits nanopatterning via the polarization domain engineering. This topical review is focused on the multiferroic system, where the ferromagnetism in the (Ga, Mn)As DMS channel is controlled by the non-volatile field effect of the spontaneous polarization. Use of ferroelectric polymer gates in such heterostructures offers a viable alternative to the traditional oxide ferroelectrics generally incompatible with DMS. Here we review the proof-of-concept experiments demonstrating the ferroelectric control of ferromagnetism, analyze the performance issues of the ferroelectric gates and discuss prospects for further development of the ferroelectric/DMS heterostructures toward the multiferroic field effect transistor.