Ovshinsky Effect by Quantum Mechanics

Authors: Thomas V. Prevenslik

Abstract:

Ovshinsky initiated scientific research in the field of amorphous and disordered materials that continues to this day. The Ovshinsky Effect where the resistance of thin GST films is significantly reduced upon the application of low voltage is of fundamental importance in phase-change - random access memory (PC-RAM) devices.GST stands for GdSbTe chalcogenide type glasses.However, the Ovshinsky Effect is not without controversy. Ovshinsky thought the resistance of GST films is reduced by the redistribution of charge carriers; whereas, others at that time including many PC-RAM researchers today argue that the GST resistance changes because the GST amorphous state is transformed to the crystalline state by melting, the heat supplied by external heaters. In this controversy, quantum mechanics (QM) asserts the heat capacity of GST films vanishes, and therefore melting cannot occur as the heat supplied cannot be conserved by an increase in GST film temperature.By precluding melting, QM re-opens the controversy between the melting and charge carrier mechanisms. Supporting analysis is presented to show that instead of increasing GST film temperature, conservation proceeds by the QED induced creation of photons within the GST film, the QED photons confined by TIR. QED stands for quantum electrodynamics and TIR for total internal reflection. The TIR confinement of QED photons is enhanced by the fact the absorbedheat energy absorbed in the GST film is concentrated in the TIR mode because of their high surface to volume ratio. The QED photons having Planck energy beyond the ultraviolet produce excitons by the photoelectric effect, the electrons and holes of which reduce the GST film resistance.

Keywords: Ovshinsky, phase change memory, PC-RAM, chalcogenide, quantummechanics, quantum electrodynamics.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1062362

References:

[1] S. R. Ovshinsky, "Reversible Electrical Switching Phenomena in Disordered Structures," Phys. Rev. Lett, vol. 21, pp. 1450-3, 1968.
[2] S.Hudgens and B.Johnson, "Phase Change Chalcogenide Nonvolatile Memory Technology," MRS Bulletin, pp. 1-4, November 2004.
[3] M. Wuttig and N. Yamada, "Phase-change materials for rewriteable data storage," Nature Materials,vol. 6, pp. 825-32, 2007.
[4] T. Prevenslik, See QED Applications http://www.nanoqed.org
[5] A. V. Akimov, et al., "Molecular Dynamics of Surface-Moving Thermally Driven Nanocars,"J. Chem. Theory Comp., vol. 4, pp. 652-656, 2008.
[6] Y. Chen and C. L. Chien, "Ballistic heat transport in nanocontacts,"Phys. Rev. B, vol. 81, 02003012(R), 2010.
[7] T.Prevenslik, "Memristors by Quantum Mechanics," Inter. Conf. on Intelligent Computing," ICIC 2011, Zhengzhou, August 11-14, 2011.
[8] T. Prevenslik, "Quantum Mechanics and Nanoelectronics,"Inter. Conf. Micro. Opto. Nanoelectronics, Venice, 28-30 November 2011.
[9] L. O. Chua,"Memristor - the missing circuit element," IEEE Trans. Circuit Theory,vol. 18, pp. 507-519, 1971.
[10] J. M. Tour, and T. He, ÔÇÿThe fourth element,"Nature, 453, pp. 42-43, 2008.
[11] D. B. Strukov, et al., "The missing memristor found," Nature, vol. 453, pp. 7191, 2008.
[12] J. Frenkel, "On Pre-Breakdown Phenomena in Insulators and Electronic Semi-Conductors," Phys. Rev., vol. 54, pp. 647, 1938.
[13] B. Chen, et al., "Improved Time-of-Flight Technique for Measuring Carrier Mobility in Thin Films of Organic Electroluminescent Materials,"Jpn. J. Appl. Phys., vol. 39, pp. 1190-1192, 2000.
[14] S. A. Kostylev, "Threshold and Filament Current Densities in Chalcogenide-Based Switches and Phase-Change-Memory Devices," IEEE Elect. Dev. Lett., vol. 30, pp. 814-6, 2009.
[15] X. Wei, et al., "Thickness Dependent Nano-Crystallization in Ge2Sb2Te5 Films and Its Effect on Devices," Jap. J. Appl. Phys., 46, 2211-4, 2007.
[16] D. H. Kim, et al., "Three-dimensional simulation model of switching dynamics in phase change random access memory cells," J. Appl. Phys., 064512,2007.