ABSTRACT
The multiple functionalities of III-nitride semiconductors enable the integration with different components into a multicomponent system with enhanced functions. Here, we propose to fabricate and characterize a monolithic InGaN photonic circuit of a transmitter, waveguide, and receiver on an III-nitride-on-silicon platform. Both the transmitter and the receiver, sharing identical InGaN/GaN multiple-quantum-well structures and fabrication procedures, work to emit light and detect light independently. The 8 µm wide and 200 µm long InGaN waveguide couples the modulated light from the transmitter and sends the guided light to the receiver, leading to the formation of an in-plane light transmission system. The induced photocurrent at the receiver is highly sensitive to the light output of the transmitter. Multi-dimensional light transmissions are experimentally demonstrated at 200 Mb/s. These multifunctional photonic circuits open feasible approaches to the development of III-nitride multicomponent systems with integrated functions for comprehensive applications in the visible region.
ABSTRACT
The spin-torque driven dynamics of antiferromagnets with Dzyaloshinskii-Moriya interaction (DMI) were investigated based on the Landau-Lifshitz-Gilbert-Slonczewski equation with antiferromagnetic and ferromagnetic order parameters (l and m, respectively). We demonstrate that antiferromagnets including DMI can be described by a 2-dimensional pendulum model of l. Because m is coupled with l, together with DMI and exchange energy, close examination of m provides fundamental understanding of its dynamics in linear and nonlinear regimes. Furthermore, we discuss magnetization reversal as a function of DMI and anisotropy energy induced by a spin current pulse.
ABSTRACT
Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can generate a significant direct-current voltage, and this rectification voltage strongly varies with the external magnetic field. We find that the rectification magnetoresistance in Al/Ge Schottky heterojunctions is as large as 250% at room temperature, which is greatly enhanced as compared with the conventional magnetoresistance of 70%. The findings of rectification magnetoresistance open the way to the new nonmagnetic Ge-based spintronics devices of large rectification magnetoresistance at ambient temperature under the alternating-current due to the simultaneous implementation of the rectification and magnetoresistance in the same devices.
ABSTRACT
The spin memristive devices combining memristance and tunneling magnetoresistance have promising applications in multibit nonvolatile data storage and artificial neuronal computing. However, it is a great challenge for simultaneous realization of large memristance and magnetoresistance in one nanoscale junction, because it is very hard to find a proper spacer layer which not only serves as good insulating layer for tunneling magnetoresistance but also easily switches between high and low resistance states under electrical field. Here we firstly propose to use nanon composite barrier layers of CoO-ZnO to fabricate the spin memristive Co/CoO-ZnO/Co magnetic tunnel junctions. The bipolar resistance switching ratio is high up to 90, and the TMR ratio of the high resistance state gets to 8% at room temperature, which leads to three resistance states. The bipolar resistance switching is explained by the metal-insulator transition of CoO(1-v) layer due to the migration of oxygen ions between CoO(1-v) and ZnO(1-v).
