We have studied the low-energy electronic structure of a Kondo insulator YbB 12 by high-resolution photoemission spectroscopy. A "Kondo peak" is observed ϳ25 meV below the Fermi level, which agrees well with the Kondo temperature, whereas the gap at the Fermi level is found much smaller, indicating that the magnetic properties at higher temperatures (կ75 K) are indeed determined by the Kondo effect in spite of the gap formation at lower temperatures. A renormalized band picture is presented to describe the coexistence of the Kondo peak and the transport gap as well as the highly asymmetric line shape of the Kondo peak.

The impact ionization phenomenon in strained-SiGe p-channel metal-oxide-semiconductor field-effect transistors (pMOSFETs) with a single quantum well (SQW) is investigated. From the universal relationship between impact ionization efficiency and the electric field in the pinch-off region, the strain-induced increase in the impact ionization efficiency of strained-SiGe pMOSFETs with different Ge contents can be attributed to a decrease in band gap energy, taking into account the increased mean free path of the hole in the SQW-SiGe channel.

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