We study theoretically the effect of the in-plane magnetic field on two-dimensional electron gas transport in GaAs/InGaAs single quantum well structure. Our results show that, due to the scatterers (GaSb quantum dots) are one-side distributed, the in-plane magnetic field leads to an anisotropic scattering probability, which results in a higher mobility along the direction perpendicular to the magnetic field. Besides, compared with the no magnetic field case, the mobility shows a parabolic increasing trend as the in-plane magnetic field strength increases.

Spinel (001)-orientated Mn3O4 thin films on Nb-doped SrTiO3 (001) substrates are fabricated via the pulsed laser deposition method. X-ray diffraction and high-resolution transmission electron microscopy indicate that the as-prepared epitaxial film is well crystallized. In the film plane the orientation relationship between the film and the substrate is [100]Mn3O4‖[110] Nb-doped SrTiO3. After an electroforming process, the film shows bipolar nonvolatile resistance switching behavior. The positive voltage bias drives the sample into a low resistance state, while the negative voltage switches it back to a high resistance state. The switching polarity is different from the previous studies. The complex impedance measurement suggests that the resistance switching behavior is of filament type. Due to the performance reproducibility and state stability, Mn3O4 might be a promising candidate for the resistive random access memory devices.

We suggest a new theoretical model to study the anisotropic scattering effect of the elongated quantum dots embedded in the GaAs/InGaAs double hetero-junction quantum well on the two-dimensional electron gas (2DEG). The elongated quantum dot (QD) with geometry which differs from ball-shaped quantum dot having isotropic cross section is assumed to be ellipsoid in the present calculation. The results show that the scattering in the direction parallel to the ellipsoid orientation (having small cross section) is weaker than that in the direction perpendicular to the ellipsoid orientation (having larger cross section) for the elongated QD when the mobile 2DEG is confined within the channel plane.

We investigated the resistive switching characteristics of Au/Ar + bombarded SrTi 0.993 Nb 0.007 O 3 /In sandwiches. The evolution of the resistive switching polarity with sweeping voltage was observed. Our experiments showed that under a macroscopic electrode the homogeneous trapping-detrapping-type conduction and filament-type conduction coexist and compete with each other. For a large sweeping voltage range, the trapping-detrapping-type conduction dominates. However, for a small range the latter dominates. If the bias voltage is too large, the filament conduction could be destroyed. These results will help deepen the understanding of the resistive switching polarity, and will aid in future device design. bipolar resistance switching, I-V curves, switching polarityBecause of the increasing demand for miniaturization in microelectronics, nonvolatile resistance random access memory (RRAM) based on sandwich unit cells composed of metal/transition metal oxide (TMO)/metal has attracted considerable attention in the past few years [1-6]. The cell resistance can be switched between different levels using an applied voltage. In a bipolar switching system, the low and high resistance states (LRS, HRS) are set and reset by the different polarity of the applied voltage. Two basic switching models have been proposed. One is the filament conduction model [4,[6][7][8][9], and the other is the homogeneous Schottky-type switching model [5,10,11]. Note that the two switching mechanisms result in different switching polarities. For n-type semiconductors and a voltage sweeping sequence of 0 VV + 0 V V   0 (here V + and V  are the maximum positive and negative applied voltages, respectively), the filament conduction model predicts that the resistance will change from a LRS to a HRS for a positive voltage, and vice versa for a negative voltage. Therefore, a "Counter- Figure-8" hysteretic current-voltage (I-V) curve is observed. However, the Schottky-type switching model changes the resistance from a HRS to a LRS for a positive bias, and vice versa for a negative bias, resulting in a "Figure-8" hysteretic I-V curve. Nb-doped SrTiO 3 (NSTO) single crystal is commonly used as a conductive substrate for functional perovskite oxide thin films. Its resistive switching characteristics have been intensively investigated [5,[11][12][13]. To the best of our knowledge, only " Figure-8" I-V curves have been reported. Recently, both "Figure-8" and "Counter-Figure-8" I-V curves were observed simultaneously in thick defective Sr 2 TiO 4 [14]and Fe-doped SrTiO 3 (STO) films [15]. However, the dynamic evolution process was not detailed in the reports.It is widely accepted that after forming process, bipolar resistive switching occurs at the active metal/TMO interface [16,17]. Therefore, we believe that by modifying the active interface we can control the bipolar resistive switching properties. In this work, we modified the NSTO surface via