Sains Malaysiana 34(2): 73-76 (2005)

Mod Fonon dan Gandingan Elektron-Fonon untuk

Kesuperkonduksian dalam Kuprat Dua Dimensi

(Phonon Mode and Electron-Phonon Coupling for Superconductivity

 in Two-Dimensional Cuprates)

Roslan Abd Shukor

Pusat Pengajian Fizik Gunaan

Fakulti Sains dan Teknologi

Universiti Kebangsaan Malaysia 43650 UKM Bangi

Selangor, D.E. Malaysia

ABSTRAK

Pemalar gandingan elektron-fonon dalam superkonduktor suhu tinggi berasaskan kuprum oksida telah diukur melalui Kaedah akustik. Hubungan terus antara pemalar gandingan elektron-fonon sistem dua dimensi senario van Hove, l_vH dengan suhu genting telah dicerap. Suhu cirian Debye bagaimana pun tidak berkorelasi dengan suhu genting. Keputusan ini menunjukkanfrekuensi Debye dan gandingan elektron-fonon dalam sistem dua dimensi saling mempengaruhi dan mempunyai kesan dalam menentukan suhu genting. Pemalar gandingan van Hove adalah dalam julat l_vH = 0.025 – 0.060 konsisten dengan pembentukan pasangan Cooper oleh interaksi elektronfonon bagi mod pernafasan oksigen tak diagonal dalam satah Cu0_2.

Katakunci: Gandingan elektron-fonon, suhu Debye, senario van Hove, mod pernafasan

ABSTRACT

The electron-phonon coupling constant in the cup rate high temperature superconductors has been determined by the acoustic method. A proportional relation between the electron-phonon coupling constant for a two dimensional system in the van Hove scenario, l_vH and the transition temperature is observed. The characteristic Debye temperature, however does not correlate with the transition temperature. Our results show the importance of interplay between the Debye frequency and electron-phonon coupling in the two dimensional system and their variations have combined effect in governing the transition temperature. The van Hove electron-phonon coupling constant is in the range of l_vH  = 0.025 – 0.060 consistent with Cooper pairs formation by non-diagonal electron-phonon interaction of the in-plane oxygen breathing mode in the CuO₂ plane.      .

Keyword: Electron-phonon coupling-debye temperature, van scenario, breathing mode.

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