Using a semiclassical Boltzmann equation, we calculate corrections to the Sharvin conductance of a wide 2DEG ballistic contact that result from an electron--electron scattering in the leads. These corrections are dominated by collisions of electrons with nearly opposite momenta that come from different reservoirs. They are positive, increase with temperature, and are strongly suppressed by a magnetic field. We argue that this suppression may be responsible for an anomalous positive magnetoresistance observed in a recent experiment.
Magnetoresistance of a 2D electron gas caused by electron interactions in the transition from the diffusive to the ballistic regime
在强磁场（omega_{c} tau > 1）中，我们在高迁移率二维电子气上观察到了由电子-电子相互作用引起的抛物线负磁阻，其范围为k_{B} T tau / hbar ~ 1，这是从扩散区到弹道区的转变。从磁阻的温度依赖性出发，得到了长程涨落势和强磁场条件下对电导率δ sigma_{xx} ^{ee}（T）的相互作用修正。结果进行了比较与预测的新理论的相互作用引起的磁阻。
Spin-dependent ballistic transport properties and electronic structures of pristine and edge-doped zigzag silicene nanoribbons: large magnetoresistance
Carrier transport in materials is often diffusive due to momentum-relaxing scattering with phonons and defects. Suppression of momentum-relaxing scattering can lead to the ballistic and hydrodynamic transport regimes, wherein complex non-Ohmic current flow patterns, including current vortices, can emerge. In the ballistic regime addressed here, transverse magnetic focusing is habitually understood in a familiar single-particle picture of carriers injected from a source, following ballistic cyclotron orbits and reaching a detector. We report on a distinctive nonlocal magnetoresistance phenomeno…
We develop a classical kinetic theory of magnetotransport of 2D electrons in narrow channels with partly diffusive boundary scattering and apply it to description of magnetoresistance measured in the temperature interval 4.2-30 K in long mesoscopic bars fabricated from high-purity GaAs quantum well structures. Both experiment and theory demonstrate a number of characteristic features in the longitudinal and Hall resistances caused by the size effect in two dimensions owing to the high ballisticity of the transport. In addition to the features described previously, we also reveal a change in th…
We report that a perpendicular magnetic field introduces an anomalous interaction correction, $δσ$, to the static conductivity of doped graphene in the ballistic regime. The correction implies that the magnetoresistance, $δρ_{xx}$ scales inversely with temperature $δρ_{xx}(T) \propto 1/T$ in a parametrically large interval. When the disorder is scalar-like, the $\propto 1/T$ behavior is the leading contribution in the crossover between diffusive regime exhibiting weak localization and quantum magnetooscillations. The behavior originates from the field-induced breaking of the chiral symmetry of…
As conductors in electronic applications shrink, microscopic conduction processes lead to strong deviations from Ohm's law. Depending on the length scales of momentum conserving ($l_{MC}$) and relaxing ($l_{MR}$) electron scattering, and the device size ($d$), current flows may shift from ohmic to ballistic to hydrodynamic regimes and more exotic mixtures thereof. So far, an in situ, in-operando methodology to obtain these parameters self-consistently within a micro/nanodevice, and thereby identify its conduction regime, is critically lacking. In this context, we exploit Sondheimer oscillation…
