arXiv subjects

Hujun Jiao

Publications and source records attributed to Hujun Jiao.

6 recordsLinked to original sources

arXiv2017

Efficient spin-current injection in single-molecule magnet junctions

We study theoretically spin transport through a single-molecule magnet (SMM) in the sequential and cotunneling regimes, where the SMM is weakly coupled to one ferromagnetic and one normalmetallic leads. By a master-equation approach, it is found that the spin polarization injected from the ferromagnetic lead is amplified and highly polarized spin-current can be generated, due to the exchange coupling between the transport electron and the anisotropic spin of the SMM. Moreover, the spin-current polarization can be tuned by the gate or bias voltage, and thus an efficient spin injection device based on the SMM is proposed in molecular spintronics.

cond-mat.mes-hall↗

arXiv2012

Tunneling anisotropic magnetoresistance in single-molecule magnet junctions

We theoretically investigate quantum transport through single-molecule magnet (SMM) junctions with ferromagnetic and normal-metal leads in the sequential regime. The current obtained by means of the rate-equation gives rise to the tunneling anisotropic magnetoresistance (TAMR), which varies with the angle between the magnetization direction of ferromagnetic lead and the easy axis of SMM. The angular dependence of TAMR can serve as a probe to determine experimentally the easy axis of SMM. Moreover, it is demonstrated that both the magnitude and sign of TAMR are tunable by the bias voltage, suggesting a promising TAMR based spintronic molecule-device.

cond-mat.mes-hall↗

arXiv2012

Spin-dependent thermoelectric transport through double quantum dots

We study thermoelectric transport through double quantum dots system with spin-dependent interdot coupling and ferromagnetic electrodes by means of the non-equilibrium Green function in the linear response regime. It is found that the thermoelectric coefficients are strongly dependent on the splitting of interdot coupling, the relative magnetic configurations and the spin polarization of leads. In particular, the thermoelectric efficiency can achieve considerable value in parallel configuration when the effective interdot coupling and tunnel coupling between QDs and the leads for spin-down electrons are small. Moreover, the thermoelectric efficiency increases with the intradot Coulomb interactions increasing and can reach very high value at an appropriate temperature. In the presence of the magnetic field, the spin accumulation in leads strongly suppresses the thermoelectric efficiency and a pure spin thermopower can be obtained.

cond-mat.mes-hall↗

arXiv2012

Spin current and polarization reversal through a single-molecule magnet with ferromagnetic electrodes

We theoretically study the spin-polarized transport through a single-molecule magnet, which is weakly coupled to ferromagnetic leads, by means of the rate-equation approach. We consider both the ferromagnetic and antiferromagnetic exchange-couplings between the molecular magnet and transported electron-spin in the nonlinear tunneling regime. For the ferromagnetic exchangecoupling, spin current exhibits step- and basin-like behaviors in the parallel and antiparallel configurations respectively. An interesting observation is that the polarization reversal of spin-current can be realized and manipulated by the variation of bias voltage in the case of antiferromagnetic exchange-coupling with antiparallel lead-configuration, which may be useful in the development of spintronic devices, while the bias voltage can only affect the magnitude of spin-polarization in the ferromagnetic coupling.

cond-mat.mes-hall↗

arXiv2009

Reduced dynamics with renormalization in solid-state charge qubit measurement

Quantum measurement will inevitably cause backaction on the measured system, resulting in the well known dephasing and relaxation. In this report, in the context of solid--state qubit measurement by a mesoscopic detector, we show that an alternative backaction known as renormalization is important under some circumstances. This effect is largely overlooked in the theory of quantum measurement.

cond-mat.mes-hall↗

arXiv2007

Full counting statistics of transport through two-channel Coulomb blockade systems

A mesoscopic Coulomb blockade system with two identical transport channels is studied in terms of full counting statistics. It is found that the average current cannot distinguish the quantum constructive interference from the classical non-interference, but the shot noise and skewness are more sensitive to the nature of quantum mechanical interference and can fulfill that task. The interesting super-Poisson shot noise is found and is demonstrated as a consequence of constructive interference, which induces an effective system with fast-and-slow transport channels. Dephasing effects on the counting statistics are carried out to display the continuous transition from quantum interfering to non-interfering transports.

cond-mat.mes-hall↗