arXiv subjects

Yang Song

Publications and source records attributed to Yang Song.

382 records · Page 22Linked to original sources

arXiv2011

Controlling the spin orientation of photoexcited electrons by symmetry breaking

We study reflection of optically spin-oriented hot electrons as a means to probe the semiconductor crystal symmetry and its intimate relation with the spin-orbit coupling. The symmetry breaking by reflection manifests itself by tipping the net-spin vector of the photoexcited electrons out of the light propagation direction. The tipping angle and the pointing direction of the net-spin vector are set by the crystal-induced spin precession, momentum alignment and spin-momentum correlation of the initial photoexcited electron population. We examine non-magnetic semiconductor heterostructures and semiconductor/ferromagnet systems and show the unique signatures of these effects.

cond-mat.mtrl-sci↗

arXiv2009

Spin transport theory in ferromagnet/semiconductor systems with non-collinear magnetization configurations

We present a comprehensive theory of spin transport in a non-degenerate semiconductor that is in contact with multiple ferromagnetic terminals. The spin dynamics in the semiconductor is studied during a perturbation of a general, non-collinear magnetization configuration and a method is shown to identify the various configurations from current signals. The conventional Landauer-Büttiker description for spin transport across Schottky contacts is generalized by the use of a non-linearized I-V relation, and it is extended by taking into account non-coherent transport mechanisms. The theory is used to analyze a three terminal lateral structure where a significant difference in the spin accumulation profile is found when comparing the results of this model with the conventional model.

cond-mat.mes-hall↗

arXiv2009

Spin relaxation of hot electrons in the Gamma-valley of zinc-blende semiconductors

We present a technique to calculate the spin relaxation of hot electrons during their energy thermalization in the Gamma-valley of zinc-blende semiconductors. The results of this model match recent experimental data and they can be used to check the applicability of spin related boundary conditions across a semiconductor/ferromagnet junction in reverse bias conditions (spin injection).

cond-mat.mes-hall↗

arXiv2007

Experimental Free Energy Surface Reconstruction From Single-Molecule Force Spectroscopy Using Jarzynski's Equality

We used the atomic force microscope to manipulate and unfold individual molecules of the titin I27 domain and reconstructed its free energy surface using Jarzynski's equality. The free energy surface for both stretching and unfolding was reconstructed using an exact formula that relates the nonequilibrium work fluctuations to the molecular free energy. In addition, the unfolding free energy barrier, i.e. the activation energy, was directly obtained from experimental data for the first time. This work demonstrates that Jarzynski's equality can be used to analyze nonequilibrium single-molecule experiments, and to obtain the free energy surfaces for molecular systems, including interactions for which only nonequilibrium work can be measured.

physics.bio-ph↗