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The quantum transport properties of a single molecular transistor are studied in the presence of an external magnetic field using the Keldysh Green function technique. The Anderson-Holstein-Caldeira-Leggett model is used to describe the single molecular transistor that consists of a molecular quantum dot (QD) coupled to two metallic leads and placed on a substrate that acts as a heat bath. The local electron-phonon (el-ph) interaction in the QD is decoupled by the Lang-Firsov (LF) transformation and the effective Hamiltonian is used to study the effects of an external magnetic field on the tunneling current and spin polarization of a SMT at zero temperature.The quantum transport properties of a single molecular transistor are studied in the presence of an external magnetic field using the Keldysh Green function technique. The Anderson-Holstein-Caldeira-Leggett model is used to describe the single molecular transistor that consists of a molecular quantum dot (QD) coupled to two metallic leads and placed on a substrate that acts as a heat bath. The local electron-phonon (el-ph) interaction in the QD is decoupled by the Lang-Firsov (LF) transformation and the effective Hamiltonian is used to study the effects of an external magnetic field on the tunneling current and spin polarization of a SMT at zero temperature.

Nanoelectronic devices have attracted significant interest for their potential as chemical/gas sensors. In this work, the performance and operation of a novel single molecular transistor based humidity sensor are demonstrated for the first time using density function theory based Ab-initio calculations. The device has a novel design, which can allow real-time detection through the charge stability diagram. It is found that this method can allow large temperature range of operation with extremely high detection sensitivity than the presently available sensors, while the simplistic design can be useful for practical experimental realisation.

In quantum interference transistors (QUITs), the current through the device is controlled by variation of the gate component of the wave function that interferes with the wave function component joining the source and the sink. Initially, mesoscopic QUITs have been studied and more recently, QUITs at the molecular scale have been proposed and implemented. Typically, in these devices the gate lead is subjected to externally adjustable physical parameters that permit interference control through modifications of the gate wave function. Here, we present an alternative model of a molecular QUIT in which the gate wave function is directly considered as a variable and the transistor operation is discussed in terms of this variable. This implies that we specify the gate current as well as the phase of the gate wave function component and calculate the resulting current through the source-sink channel. Thus, we extend on prior works that focus on the phase of the gate wave function component as a control parameter while having zero or certain discrete values of the current. We address a large class of systems, including finite graphene flakes, and obtain analytic solutions for how the gate wave function controls the transistor.