Tunneling of spin-polarized charge carriers in La0.8Ag0.1MnO3+δ film with variant structure: Magnetotransport and magnetooptical data

2005 ◽  
Vol 31 (6) ◽  
pp. 484-487 ◽  
Author(s):  
Yu. P. Sukhorukov ◽  
A. V. Telegin ◽  
E. A. Gan’shina ◽  
N. N. Loshkareva ◽  
A. R. Kaul’ ◽  
...  
Science ◽  
2019 ◽  
Vol 363 (6422) ◽  
pp. 54-57 ◽  
Author(s):  
Fabien Lafont ◽  
Amir Rosenblatt ◽  
Moty Heiblum ◽  
Vladimir Umansky

The quantum Hall effect, observed in a two-dimensional (2D) electron gas subjected to a perpendicular magnetic field, imposes a 1D-like chiral, downstream, transport of charge carriers along the sample edges. Although this picture remains valid for electrons and Laughlin’s fractional quasiparticles, it no longer holds for quasiparticles in the so-called hole-conjugate states. These states are expected, when disorder and interactions are weak, to harbor upstream charge modes. However, so far, charge currents were observed to flow exclusively downstream in the quantum Hall regime. Studying the canonical spin-polarized and spin-unpolarized v = 2/3 hole-like states in GaAs-AlGaAs heterostructures, we observed a significant upstream charge current at short propagation distances in the spin unpolarized state.


2009 ◽  
Vol 79 (16) ◽  
Author(s):  
Raghava P. Panguluri ◽  
P. Kharel ◽  
C. Sudakar ◽  
R. Naik ◽  
R. Suryanarayanan ◽  
...  

2011 ◽  
Vol 25 (12) ◽  
pp. 1601-1610
Author(s):  
X. J. LIU ◽  
Z. AN ◽  
S. J. XIE

Both polarons and bipolarons are composite particles with internal structures in nondegenerate conjugated polymers. A bipolaron is a spinless species with charge ±2|e|, while a polaron is a spin-bearing one (spin 1/2, charge ±|e|). Serving as charge carriers, they play an important role in the transport properties of polymer-based optoelectronic devices. By using a nonadiabatic dynamic method, the motion of a bipolaron under an external electric field is theoretically investigated in a conjugated polymer with magnetic impurities. Our results show that a bipolaron can pass through the magnetic impurities, or break down into two polarons with different spins, or be trapped by the magnetic impurities, depending on the width of the impurity region. When the width of the impurity region is comparable to the polaron width, the bipolaron is transformed into two polarons easily. As a polaron and a bipolaron possess different spin characteristics, the decomposition of bipolarons induced by the magnetic impurities may have important effect on the spin polarized transportation.


2019 ◽  
Vol 59 (1) ◽  
Author(s):  
Dominik Kreil ◽  
Michaela Haslhofer ◽  
Helga M. Böhm

The growing precision of optical and scattering experiments necessitates a better understanding of the influence of damping onto the collective mode of sheet electrons. As spin-polarized systems are of particular interest for spintronic applications, we here report spin-sensitive linear response functions of graphene, which give access to chargeand spin-density related excitations. We further calculate the reflectivity of graphene on an SiO2 surface, a setup used in s-wave scanning near-field microscopy. Increasing the partial spin-polarization of the graphene charge carriers leads to a significant broadening and shift of the plasmon mode, due to single-particle interband transitions of the minority spin carriers. We also predict an antiresonance in the longitudinal magnetic response function, similar to that of semiconductor heterostructures.


2020 ◽  
Vol 46 (7) ◽  
pp. 724-733
Author(s):  
L. А. Pastur ◽  
V. V. Slavin ◽  
A. V. Yanovsky

2020 ◽  
Vol 128 (1) ◽  
pp. 43
Author(s):  
А.В. Телегин ◽  
В.А. Бессонова ◽  
Ю.П. Сухоруков ◽  
А.П. Носов ◽  
Е.А. Ганьшина

A correlation was found between the magnetoreflection of natural light and tunneling magnetoresistance in La2 / 3Ba1 / 3MnO3 films with a variant structure grown on ZrO2 (Y2O3) substrates. It was shown that the magnetoreflection as well as the colossal magnetoresistance, is maximum in the region of magnetic ordering near room temperature (Tc ~ 295 K) of the films. The magnetoreflection spectra of a La2 / 3Ba1 / 3MnO3 film with the variant structure are formed by the same mechanisms as in the case of films without the variant structure and can be described in terms of the theory of the magnetorefractive effect. The field and temperature dependences of magnetoreflection demonstrate the presence of an additional low-temperature contribution to the reflection of the La2 / 3Ba1 / 3MnO3 film due to tunneling of spin-polarized electrons through the boundaries of structural domains.


2021 ◽  
Vol 7 (30) ◽  
pp. eabh2233
Author(s):  
Valentin Crépel ◽  
Liang Fu

We introduce a general mechanism for superconductivity in Fermi systems with strong repulsive interaction. Because kinetic terms are small compared to the bare repulsion, the dynamics of charge carriers is constrained by the presence of other nearby carriers. By treating kinetic terms as a perturbation around the atomic limit, we show that pairing can be induced by correlated multiparticle tunneling processes that favor two itinerant carriers to be close together. Our analytically controlled theory provides a quantitative formula relating Tc to microscopic parameters, with maximum Tc reaching about 10% of the Fermi temperature. Our work demonstrates a powerful method for studying strong coupling superconductivity with unconventional pairing symmetry. It also offers a realistic new route to realizing finite angular momentum superfluidity of spin-polarized fermions in optical lattice.


2010 ◽  
Vol 25 (9) ◽  
pp. 1799-1802 ◽  
Author(s):  
P.S. Solanki ◽  
R.R. Doshi ◽  
U.D. Khachar ◽  
M.V. Vagadia ◽  
A.B. Ravalia ◽  
...  

The structural, transport, and magnetotransport properties of single-phase, homogeneous nanostructured La0.7Sr0.3MnO3 (LSMO) manganites synthesized by the coprecipitation route were investigated and the effect of sintering temperature on the microstructure of LSMO compounds was studied. A strong dependence of transport and magnetotransport behavior on the microstructure and nature of grain boundaries has been observed in the single-phase LSMO sintered at various temperatures. High-field magnetoresistance (HFMR) at room temperature is found to increase [13% (LS6) to 25% (LS9)] while low temperature (5 K) magnetoresistance decreases [75% (LS6) to 46% (LS9)] under 9 T field with increase in sintering temperature, which has been attributed to the spin-polarized tunneling and spin-dependent scattering of charge carriers.


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