Gate-controllable spin-battery

We propose a gate-controllable spin-battery for spin current. The spin-battery consists of a lateral double quantum dot under a uniform magnetic field. A finite DC spin-current is driven out of the device by controlling a set of gate voltages. Spin-current can also be delivered in the absence of charge-current. The proposed device should be realizable using present technology at low temperature.Comment: 3 pages, 3 figures, accepted by Appl. Phys. Let

New Class of Two-Loop Neutrino Mass Models with Distinguishable Phenomenology

We discuss a new class of neutrino mass models generated in two loops, and explore specifically three new physics scenarios: (A) doubly charged scalar, (B) dark matter, and (C) leptoquark and diquark, which are verifiable at the 14 TeV LHC Run-II. We point out how the different Higgs insertions will distinguish our two-loop topology with others if the new particles in the loop are in the simplest representations of the SM gauge group

Hexagonal SU(3) Unification and its Manifestation at the TeV Scale

We consider $SU(3)_{C}\times SU(2)_{AL}\times SU(2)_{BL}\times U(1)_{Y}$ as the low-energy subgroup of supersymmetric $SU(3)^{6}$ unification. This may imply small deviations from quark-lepton universality at the TeV scale, as allowed by neutron-decay data. New particles are predicted with specific properties. We discuss in particular the new heavy gauge bosons corresponding to $SU(2)_{AL} \times SU(2)_{BL} \to SU(2)_L$

Nanoscale Mechanical Switching of Ferroelectric Polarization Via Flexoelectricity

Flexoelectric coefficient is a fourth-rank tensor arising from the coupling between strain gradient and electric polarization and thus exists in all crystals. It is generally ignored for macroscopic crystals due to its small magnitude. However, at the nanoscale, flexoelectric contributions may become significant and can potentially be utilized for device applications. Using the phase-field method, we study the mechanical switching of electric polarization in ferroelectric thin films by a strain gradient created via an atomic force microscope tip. Our simulation results show good agreement with existing experimental observations. We examine the competition between the piezoelectric and flexoelectric effects and provide an understanding of the role of flexoelectricity in the polarization switching. Also, by changing the pressure and film thickness, we reveal that the flexoelectric field at the film bottom can be used as a criterion to determine whether domain switching may happen under a mechanical force