The most important barrier which is significantly limiting the expected evolution of current computer transistor technology (CMOS) is a fundamental limit, coming from Boltzmann's equation, on the further lowering of line voltage from present values (1 V). Power, proportional to voltage squared, no longer scales with transistor size and due to power limitations CMOS clock speeds have plateaued since 2003. This has strongly affected the theoretical / computational community as our software no longer increases in efficiency with each hardware generation without substantial effort on the part of research groups.We have developed a new type of computer switch, the piezoelectronic transistor (PET) (Martyna et al, Adv. Mat. 24 , 3672 (2012)) given in Fig. 1, that functions by transducing an input voltage signal into acoustic form via the action of a piezoelectric element (PE). The acoustic pulse then acts on a piezoresistive element (PR) compressing it and triggering a continuous metal insulator transition thereby transducing the signal back into voltage. This new mechanism allows voltage to be reduced 10x from current hardware permitting higher clock speeds to be sustained.In this lecture, the properties of key piezoresistive materials, SmSe and SmTe, under applied stress will be described using a fully relativistic LSDA+U treatment. We compare the theoretical results to optical and electrical measurements under hydrostatic stress (Phys. Rev. Lett. 25 1440 (1970)) performed at Bell Labs and under uniaxial load as in the PET device (Nano Lett. ASAP DOI: 10.1021/nl401710f (2013)) performed recently by our group at IBM. Results of NEGF studies of transport through thin (nm) layers of SmSe are also given.   Figure 1  : PiezoElectronic transistor with gate, common, and sense terminals, a piezoelectric (PE) element between common and gate terminals and a piezoresistive (PR) element between common and sense terminals. The High Yield strength Material (HYM) surround mechanically clamps the device.

Optical and electrical properties of Samarium mono-chalcogenides with pressure for use in next generation devices: A relativistic DFT+U study

247th National Meeting (2014)

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