Donor states in modulation-doped Si/SiGe heterostructures

We present a unified approach for calculating the properties of shallow donors inside or outside heterostructure quantum wells. The method allows us to obtain not only the binding energies of all localized states of any symmetry, but also the energy width of the resonant states which may appear when a localized state becomes degenerate with the continuous quantum well subbands. The approach is non-variational, and we are therefore also able to evaluate the wave functions. This is used to calculate the optical absorption spectrum, which is strongly non-isotropic due to the selection rules. The results obtained from calculations for Si/Si$_{1-x}$Ge$_x$ quantum wells allow us to present the general behavior of the impurity states, as the donor position is varied from the center of the well to deep inside the barrier. The influence on the donor ground state from both the central-cell effect and the strain arising from the lattice mismatch is carefully considered.Comment: 17 pages, 10 figure

Some Transaction Cost Effects of Authoritarian Management

This paper studies the transaction cost economizing effects of authoritarian management in organizations and systems subject to higher transaction costs originating from various sources. We analyze the nature, mechanisms, and transaction cost aspects of the authoritarian management style. We argue that the higher the transaction costs of internal organization, the more autocratic the manager is likely to be. We discuss the features of authoritarian managers, illustrating some of our key hypotheses with the example of Henry Ford and his running of the Ford Motor Company. In the context of non-market economies, we relate authoritarian leadership to economic centralism in high transaction cost systems such as East European societies with significant transactional or organizational opportunism, as well as other sources of market failure