We propose a spin transistor using only non-magnetic materials that exploits the characteristics of bulk inversion asymmetry (BIA) in (110) symmetric quantum wells. We show that extremely large spin splittings due to BIA are possible in (110) InAs/GaSb/AlSb heterostructures, which together with the enhanced spin decay times in (110) quantum wells demonstrates the potential for exploitation of BIA effects in semiconductor spintronics devices. Spin injection and detection is achieved using spin-dependent resonant interband tunneling and spin transistor action is realized through control of the electron spin lifetime in an InAs lateral transport channel using an applied electric field (Rashba effect). This device may also be used as a spin valve, or a magnetic field sensor. The electronic structure and spin relaxation times for the spin transistor proposed here are calculated using a nonperturbative 14-band k · p nanostructure model.

Fundamental physical properties limiting the performance of spin field effect transistors are compared to those of ordinary (charge-based) field effect transistors. Instead of raising and lowering a barrier to current flow these spin transistors use static spin-selective barriers and gate control of spin relaxation. The different origins of transistor action lead to distinct size dependences of the power dissipation in these transistors and permit sufficiently small spin-based transistors to surpass the performance of charge-based transistors at room temperature or above. This includes lower threshold voltages, smaller gate capacitances, reduced gate switching energies and smaller source-drain leakage currents.Comment: 4 pages including 3 figures, APL in pres

The strong spin-orbit interaction in the organic-inorganic perovskites tied to the incorporation of heavy elements (e.g. Pb, I) makes these materials interesting for applications in spintronics. Due to a lack of inversion symmetry associated with distortions of the metal-halide octahedra, the Rashba effect (used e.g. in spin field-effect transistors and spin filters) has been predicted to be much larger in these materials than in traditional III-V semiconductors such as GaAs, supported by the recent observation of a near record Rashba spin splitting in CH 3 NH 3 PbBr 3 using angle-resolved photoemission spectroscopy (ARPES). More experimental studies are needed to confirm and quantify the presence of Rashba effects in the organic-inorganic perovskite family of materials. Here we apply time-resolved circular dichroism techniques to the study of carrier spin dynamics in a 2D perovskite thin film [(BA) 2 MAPb 2 I 7 ; BA = CH 3 (CH 2 ) 3 NH 3 , MA = CH 3 NH 3 ]. Our findings confirm the presence of a Rashba spin splitting via the dominance of precessional spin relaxation induced by the Rashba effective magnetic field. The size of the Rashba spin splitting in our system was extracted from simulations of the measured spin dynamics incorporating LO-phonon and electron-electron scattering, yielding a value of 10 meV at an electron energy of 50 meV above the band gap, representing a 20 times larger value than in GaAs quantum wells.The hybrid organic-inorganic perovskites have gained considerable attention in recent years due to their outstanding performance as absorbing layers in photovoltaics [1]. This success has led to a comprehensive research effort with the aim to unravel their photophysical properties [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], and to move beyond CH 3 NH 3 PbI 3 and explore other material compositions including 2D perovskites [19][20][21][22][23][24]. This burgeoning family of materials offers properties that can be tailored to a broad range of applications in opto-electronics, including photovoltaics [1,23,25], field-effect transistors [26,27], hard radiation detectors [28], light-emitting diodes [29][30][31], lasers [32], and optical sensors [33].The hybrid perovskites are characterized by strong spin-orbit coupling (SOC) tied to the constituent heavy elements [34]. These strong spin-orbit effects make the perovskite family of materials attractive for applications in semiconductor spintronics and spin optoelectronics [35][36][37][38][39][40][41][42][43][44][45]. SOC leads to a giant (∼1 eV) splitting of the lowest two conduction bands and influences the band gap and carrier effective masses [46,47]. In conjunction with a lack of inversion symmetry, SOC also leads to an effective magnetic field that lifts the degeneracy of the carrier spin states within each band [35]. While this effect has many origins in semiconductors tied to different sources of inversion asymmetry [48][49][50][51][52], it is most commonly referred to as the Rashba effect after Bychkov and Rashba analyzed the ...

We report an enhancement of the electron spin relaxation time (T1) in a (110) InAs/GaSb superlattice by more than an order of magnitude (25 times) relative to the corresponding (001) structure. The spin dynamics were measured using polarization sensitive pump probe techniques and a mid-infrared, subpicosecond PPLN OPO. Longer T1 times in (110) superlattices are attributed to the suppression of the native interface asymmetry and bulk inversion asymmetry contributions to the precessional D'yakonov Perel spin relaxation process. Calculations using a nonperturbative 14-band nanostructure model give good agreement with experiment and indicate that possible structural inversion asymmetry contributions to T1 associated with compositional mixing at the superlattice interfaces may limit the observed spin lifetime in (110) superlattices. Our findings have implications for potential spintronics applications using InAs/GaSb heterostructures.Comment: 4 pages, 2 figure

We demonstrate adiabatic rapid passage on a subpicosecond time scale in a single semiconductor quantum dot, enabling the exploration of a regime of strong (and rapidly varying) Rabi energies for optical control of excitons. An observed dependence of the exciton inversion efficiency on the sign of the pulse chirp demonstrates the dominance of phonon-mediated dephasing, which is suppressed for positive chirp at low temperature. Our findings will support the realization of dynamical decoupling strategies and suggest that multiphonon emission and/or non-Markovian effects should be taken into account.