Search

Nodal link semimetals as a type of topological semimetals are characterized by the nodal link rings in the Brillouin zone. The magneto-optical conductivity of nodal link semimetals is investigated numerically based on a system with a magnetic field. We find that in the system, the Landau levels (LLs) and magnetic field show a relationship of three halves power, which can lead to an intricate curved LLs. Due to the rich structure of LLs, we divided the LLs into four different regions to calculate the magneto-optical conductivity. We calculated the absorption peaks of longitudinal and Hall conductance of a neutral system and with different chemical potential. We find that the absorption peaks of longitudinal conductance are in a curved background in the whole range of magnetic field. When chemical potential is tuned to pass through the LLs, there are not only the intraband transition but also weak redistributed peaks in the low frequency. From the transition peaks of Hall conductance, we can find that there are several negative peaks because of the striking LLs spectrum structure. This will provide a feasible way to distinguish nodal link semimetals from other materials. [ABSTRACT FROM AUTHOR]

The gapless edge states with a certain spin and valley index can be realized in topological domain walls. In this work, we study various domain walls thoroughly and demonstrate that multiple kinds of edge states with a perfect spin and valley polarization can be realized, leading to the possibility of establishing spin filters and spin-valley filters. Moreover, the spin and valley index of the edge states can be tuned by an external electric field. We also investigate the finite size effect on the edge states when two domain walls approach each other. Generally, the finite size effect can cause the hybridization of edge states and open a gap. We find that the evolutions of the bandgap as a function of the finite size effect for different topological edge states are distinguished from each other. [ABSTRACT FROM AUTHOR]

The synaptic behavior of the Ni–Co layered double hydroxide-based memristor was demonstrated. The modulation effect of pulse amplitude, duration, and excitation interval on the conductance of memristor is analyzed. On account of analog resistive switching features, and the nonlinear transmission characteristics of synapses, pulse-time-dependent plasticity, long-term/short-term memory, and "learning" and "forgetting" behaviors of synapses are simulated and carried out. The analog bipolar resistance switch was ascribed to the formation and breakdown of oxygen filaments formed in Ni–Co layered double hydroxides films. This kind of memristor with an analog resistance switch is very promising to provide an implementation method for the development of electronic synapse function. [ABSTRACT FROM AUTHOR]

Synaptic behavior simulation in transistors based on MoS2 has been reported. MoS2 was utilized as the active layer to prepare ambipolar thin-film transistors. The excitatory postsynaptic current phenomenon was simulated, observing a gradual voltage decay following the removal of applied pulses, ultimately resulting in a response current slightly higher than the initial current. Subsequently, ±5 V voltages were separately applied for ten consecutive pulse voltage tests, revealing short-term potentiation and short-term depression behaviors. After 92 consecutive positive pulses, the device current transitioned from an initial value of 0.14 to 28.3 mA. Similarly, following 88 consecutive negative pulses, the device current changed, indicating long-term potentiation and long-term depression behaviors. We also employed a pair of continuous triangular wave pulses to evaluate paired-pulse facilitation behavior, observing that the response current of the second stimulus pulse was ∼1.2× greater than that of the first stimulus pulse. The advantages and prospects of using MoS2 as a material for thin-film transistors were thoroughly displayed. [ABSTRACT FROM AUTHOR]