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Electron-electron interaction correction and magnetoresistance in tilted fields in Si-based 2D systems

We study diffusive electron-electron interaction correction to conductivity by analyzing simultaneously $ρ_{xx}$ and $ρ_{xy}$ for disordered 2D electron systems in Si in tilted magnetic field. Tilting the field is shown to be a straightforward tool to disentangle spin and orbital effects. In particular, by changing the tilt angle we prove experimentally that in the field range $gμ_BB>k_BT$ the correction depends on modulus of magnetic field rather than on its direction, which is expected for a system with isotropic $g$-factor. In the high-field limit the correction behaves as $\ln (B)$, as expected theoretically (Lee, Ramakrishnan, Phys. Rev. B{\bf 26}, 4009 (1982)). Our data prove that the diffusive electron-electron interaction correction to conductivity is not solely responsible for the huge and temperature dependent magnetoresistance in parallel field, typically observed in Si-MOSFETs.