arXiv subjects

Zhigang Zou

Publications and source records attributed to Zhigang Zou.

3 recordsLinked to original sources

arXiv2017

Controllable transport of a skyrmion in a ferromagnetic narrow channel with voltage-controlled magnetic anisotropy

Magnetic skyrmions have potential applications in next-generation spintronics devices with ultralow energy consumption. In this work, the current-driven skyrmion motion in a narrow ferromagnetic nanotrack with voltage-controlled magnetic anisotropy (VCMA) is studied numerically. By utilizing the VCMA effect, the transport of skyrmion can be unidirectional in the nanotrack, leading to a one-way information channel. The trajectory of the skyrmion can also be modulated by periodically located VCMA gates, which protects the skyrmion from destruction by touching the track edge. In addition, the location of the skyrmion can be controlled by adjusting the driving pulse length in the presence of the VCMA effect. Our results provide guidelines for practical realization of the skyrmion-based information channel, diode, and racetrack memory.

cond-mat.mes-hall↗

arXiv2013

Enhanced Hot-Carrier Luminescence in Multilayer Reduced Graphene Oxide Nanospheres

We report a method to promote photoluminescence emission in graphene materials by enhancing carrier scattering instead of directly modifying band structure in multilayer reduced graphene oxide (rGO) nanospheres. We intentionally curl graphene layers to form nanospheres by reducing graphene oxide with spherical polymer templates to manipulate the carrier scattering. These nanospheres produce hot-carrier luminescence with more than ten-fold improvement of emission efficiency as compared to planar nanosheets. With increasing excitation power, hot-carrier luminescence from nanospheres exhibits abnormal spectral redshift with dynamic feature associated to the strengthened electron-phonon coupling. These experimental results can be well understood by considering the screened Coulomb interactions. With increasing carrier density, the reduced screening effect promotes carrier scattering which enhances hot-carrier emission from such multilayer rGO nanospheres. This carrier-scattering scenario is further confirmed by pump-probe measurements.

cond-mat.mes-hall↗

arXiv2009

The Spontaneous Generation of Magnetic Moment of Beryllium Dimer on Graphene

Graphene has various potential applications in electronics and scientists are seeking to introduce magnetic properties on graphene. Here we report our theoretical findings that a local magnetic moment as large as 1 $μ_B$ can be generated from the adsorption of the diamagnetic beryllium dimer on perfect diamagnetic graphene. Unexpectedly the adsorption system is remarkably stable as evidenced by the binding energy of 1.04 eV, indicating that the formation of beryllium dimer is energetically much favorable. Analyses reveal that the magnetic moment and stability is originated from the spontaneous transfer of one electron from the anti-bonding orbital of the dimer to graphene.

cond-mat.mtrl-sci↗