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Published byBertha Franklin Modified over 8 years ago
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By Supervisor Urbashi Satpathi Dr. Prosenjit Singha De0
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Experimental background Motivation PLDOS, Injectivity, Emissivity, Injectance, Emitance, LDOS, DOS Paradox and its practical implication Experimental background Motivation PLDOS, Injectivity, Emissivity, Injectance, Emitance, LDOS, DOS Paradox and its practical implication
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Schematic description of experimental set up [ R. Schuster, E. Buks, M. Heiblum, D. Mahalu, V. Umansky and Hadas Shtrikman, Nature 385, 417 (1997) ]
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Collector voltage, V CB
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Analyticity Hilbert Transform relates the amplitude and argument
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What information we can get from phase shift ?
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Apparently does not follow Friedel sum rule (FSR) However if carefully seen w.r.t Fano resonance (FR) c an be understood from FSR Besides there is a paradox at FR that can have tremendous practical implication.
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Larmor precision time (LPT) Injectivity
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Why injectivity is physical?
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Local density of states Density of states This is an exact expression.
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In semi-classical limit Hence,, is FSR (semi classical). [ M. Büttiker, Pramana Journal of Physics 58, 241 (2002) ]
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and, is semi classical injectance. [ C. R. Leavens and G. C. Aers, Phys. Rev. B 39, 1202 (1989), E. H. Hauge, J. P. Falck, and T. A. Fjeldly, Phys. Rev. B 36, 4203 (1987) ]
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Incident wave packet Scattered wave packet
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i.e. in semi classical case, density of states is related to energy derivative of scattering phase shift. Considering no reflected part (E>>V), and no dispersion of wave packet, is stationary phase approximation.
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The confinement potential, The scattering potential, is symmetric in x-direction
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The Schrödinger equation of motion in the defect region is, In the no defect region,, where, and,, is the energy of incidence.
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For symmetric potentials, For, where, w and, At resonance,
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The potential at X, Internal wave function Modes of the quantum wire Injectance from wave function is,
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, where,, and
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Injectance from wave function is, Semi classical injectance is,,
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and
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There is a paradox at Fano resonance The semi classical injectivity gets exact at FR Useful for experimentalists
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1.Leggett's conjecture for a mesoscopic ring P. Singha Deo Phys. Rev. B {\bf 53}, 15447 (1996). 2. Nature of eigenstates in a mesoscopic ring coupled to a side branch. P. A. Sreeram and P. Singha Deo Physica B {\bf 228}, 345(1996. 3.Phase of Aharonov-Bohm oscillation in conductance of mesoscopic systems. P. Singha Deo and A. M. Jayannavar. Mod. Phys. Lett. B {\bf 10}, 787 (1996). 4.Phase of Aharonov-Bohm oscillations: effect of channel mixing and Fano resonances. P. Singha Deo Solid St. Communication {\bf 107}, 69 (1998). 5.Phase slips in Aharonov-Bohm oscillations P. Singha Deo Proceedings of International Workshop on $``$Novelphysics in low dimensional electron systems", organized byMax-Planck-Institut Fur Physik Komplexer Systeme, Germanyin August, 1997.\\Physica E {\bf 1}, 301 (1997). 6.Novel interference effects and a new Quantum phase in mesoscopicsystems P. Singha Deo and A. M. Jayannavar, Pramana Journal of Physics, {\bf 56}, 439 (2001). Proceedings of the Winter Institute on Foundations of Quantum Theoryand Quantum Optics, at S.N. Bose Centre,Calcutta, in January 2000. 7.Electron correlation effects in the presence of non-symmetry dictated nodes P. Singha Deo Pramana Journal of Physics, {\bf 58}, 195 (2002) 8.Scattering phase shifts in quasi-one-dimension P. Singha Deo, Swarnali Bandopadhyay and Sourin Das International Journ. of Mod. Phys. B, {\bf 16}, 2247 (2002) 9.Friedel sum rule for a single-channel quantum wire Swarnali Bandopadhyay and P. Singha Deo Phys. Rev. B {\bf 68} 113301 (2003) 10. Larmor precession time, Wigner delay time and the local density of states in a quantum wire. P. Singha Deo International Journal of Modern Physics B, {\bf 19}, 899 (2005) 11. Charge fluctuations in coupled systems: ring coupled to a wire or ring P. Singha Deo, P. Koskinen, M. Manninen Phys. Rev. B {\bf 72}, 155332 (2005). 12. Importance of individual scattering matrix elements at Fano resonances. P. Singha Deo} and M. Manninen Journal of physics: condensed matter {\bf 18}, 5313 (2006). 13. Nondispersive backscattering in quantum wires P. Singha Deo Phys. Rev. B {\bf 75}, 235330 (2007) 14. Friedel sum rule at Fano resonances P Singha Deo J. Phys.: Condens. Matter {\bf 21} (2009) 285303. 15. Quantum capacitance: a microscopic derivation S. Mukherjee, M. Manninen and P. Singha Deo Physica E (in press). 16. Injectivity and a paradox U. Satpathy and P. Singha Deo International journal of modern physics (in press).
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