Browsing by Author "Meikap, AK"

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Anomalous temperature and disorder dependence of the electron-phonon scattering time in impure metals
(2003-05-01)
Lin, JJ
;
Zhong, YL
;
Kao, LY
;
Meikap, AK
;
物理研究所
We have measured the electron-phonon scattering time, tau(ep), in disordered metals at liquid-helium temperatures, using weak-localization method. The temperature and disorder dependence of tau(ep), is determined for AgPd and AuPd thick films, and V100-xAlx alloys. In all three cases, we find an anomalous temperature and disorder dependence of tau(ep)(-1) proportional to T(2)l where l is the electron elastic mean free path. This temperature and disorder behavior cannot be explained in terms of current theoretical concepts for the electron-phonon interaction in impure conductors. Current theory predicts a form of either tau(ep)(-1) proportional to T(4)l or tau(ep)(-1) proportional to T(2)l(-1) in the dirty limit, depending on the nature of the defects. (C) 2003 Elsevier Science B.V. All rights reserved.
Anomalous temperature and disorder dependences of electron-phonon scattering rate in impure V1-xAlx alloys
(2004-06-01)
Meikap, AK
;
Chen, YY
;
Lin, JJ
;
電子物理學系
;
物理研究所
Using weak-localization studies, we have measured the electron-phonon scattering time tau(ep) in a series of V1-xAlx alloys having the characteristic of ql<<1, where q is the wave number of the thermal phonons and l is the electron elastic mean free path. We find an anomalous electron-phonon scattering rate obeying a quadratic temperature dependence as well as a linear mean-free-path dependence, i.e., tau(ep)(-1)similar toT(2)l. This result cannot be explained in terms of existing theories for the electron-phonon interaction in impure conductors.
Weak localization and electron-electron interaction in disordered V80Al20-xFex alloys at low temperature
(2004-08-02)
Biswas, D
;
Meikap, AK
;
Chattopadhyay, SK
;
Chatterjee, SK
;
Lin, JJ
In this Letter we report on the electrical resistivity and magneto-resistivity of disordered V80Al20-xFex alloys in the temperature range 1.5 less than or equal to T less than or equal to 300 K and analyze them in the light of weak localization and electron-electron interaction. The low temperature zero field resistivity obeys a T-1/2 law, which is explained by electron-electron interaction. The low field magneto-resistivity is described by weak localization theory under strong spin-orbit interaction. The electron-phonon scattering rate obeys a quadratic temperature dependence. This observation is interpreted by the existing theories of electron-phonon interaction. (C) 2004 Elsevier B.V. All rights reserved.