Electron Spin Polarization in Resonant Interband Tunneling Devices

We study spin-dependent interband resonant tunneling in double-barrier InAs/AlSb/ GaMnSb heterostructures. We demonstrate that these structures can be used as spin filters utilizing spin-selective tunneling of electrons through the light-hole resonant channel. High densities of the spin polarized electrons injected into bulk InAs make spin resonant tunneling devices a viable alternative for injecting spins into a semiconductor. Another striking feature of the proposed devices is the possibility of inducing additional resonant channels corresponding to the heavy holes. This can be implemented by saturating the in-plane magnetization in the quantum well.Comment: 11 pages, 4 eps figure

Electronic Transport in Hybrid Mesoscopic Structures: A Nonequilibrium Green Function Approach

We present a unified transport theory of hybrid structures, in which a confined normal state ($N$) sample is sandwiched between two leads each of which can be either a ferromagnet ($F$) or a superconductor ($S$) via tunnel barriers. By introducing a four-dimensional Nambu-spinor space, a general current formula is derived within the Keldysh nonequilibrium Green function formalism, which can be applied to various kinds of hybrid mesoscopic systems with strong correlations even in the nonequilibrium situation. Such a formula is gauge invariant. We also demonstrate analytically for some quantities, such as the difference between chemical potentials, superconductor order parameter phases and ferromagnetic magnetization orientations, that only their relative value appears explicitly in the current expression. When applied to specific structures, the formula becomes of the Meir-Wingreen-type favoring strong correlation effects, and reduces to the Landauer-B\"uttiker-type in noninteracting systems such as the double-barrier resonant structures, which we study in detail beyond the wide-band approximation.Comment: 24 pages, 12 eps figures, Revtex

How ‘bad apples’ spoil the bunch: Faultlines, emotional levers and exclusion in the workplace

Just as a rotten apple makes other apples around it begin to decay, so too can people influence others within their vicinity, particularly in terms of destructive emotions and behaviors. Trevino and Youngblood (1990) adopted the term ‘bad apples’ to describe individuals who engage in unethical behaviors and who also influence others to behave in a similar manner. In this chapter, the ‘bad apple’ metaphor is adopted to describe the employee whose actions and interactions create and maintain destructive faultlines and unethical exclusion behaviors that negatively impact the emotional well-being and effective and ethical performance of the team. In particular, the chapter examines the way in which ‘bad apples’ use destructive emotion management skills through the manipulation of emotional levers of others, what motivates them to do so and the implications it may have on management