Electron transport through a diatomic molecule

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• 作者：Muhammad Imran ^{imran1gee@gmail.com" class="auth_mail}
• 关键词：NEGF (non-equilibrium Green壮s function) ; GMET (generalized master equation theory) ; LCAO (linear combinations of atomic orbitals) ; ME (molecular electronics)
• 刊名：Physica B
• 出版年：1 August 2014
• 年：2014
• 卷：446
• 期：Complete
• 页码：1-5
• 全文大小：373 K

文摘

Electron transport through a diatomic molecular tunnel junction shows wave like interference phenomenon. By using Keldysh non-equilibrium Green壮s function (NEGF) theory, we have explicitly presented current and differential conductance calculation for a diatomic molecular and two isolated atoms (two atoms having zero hybridization between their energy orbitals) tunnel junctions. In case of a diatomic molecular tunnel junction, Green壮s function propagators entering into current and differential conductance formula interfere constructively for a molecular anti-bonding state and destructively for bonding state. Consequently, conductance through a molecular bonding state is suppressed, and to conserve current, conductance through anti-bonding state is enhanced. Therefore, current steps and differential conductance peaks amplitude show asymmetric correspondence between molecular bonding and anti-bonding states. Interestingly, for a diatomic molecule, comprising of two atoms of same energy level, these propagators interfere completely destructively for molecular bonding state and constructively for molecular anti-bonding state. Hence under such condition, a single step or a single peak is shown up in current versus voltage or differential conductance versus voltage studies.