Study Of The Transport Properties Of The Superconducting Tunnelling Junctions

This paper presents a brief introduction to the Bogoliubov-de Gennes(BdG)e-quation and Blonder-Tinkham-Klapwijk(BTK)formalism,which are widely used ap-proaches to the superconductor tunnelling junctions.First,the conductance spectrum of the normal metal/ferromagnetic insulator/triplet superconductor junction is investigated under the Blonder-Tinkham-Klapwijk formal-ism.The superconductor is assumed in the unitary phase.We find that the zero-bias conductance is robustly quantized at 4e2/h when the magnetization of the ferromag-netic insulator is perpendicular to the d vector of the triplet superconductor.When the magnetization is not perpendicular to the d vector,the zero-bias peak vanishes and splits into two peaks.Next,the Josephson effect in a spin superconductor is investigated.After a brief introduction to the spin superconductor and spin current,the Andreev levels,free ener-gy and current phase relation of the spin superconductor/insultor/spin superconductor(SIS)junction and spin superconductor/normal metal/spin superconductor(SNS)junc-tion are derived analytically by using the BdG equation.The 0-7r transition with no need for the exchange field is found in both of the two junctions,which is different of the general charge superconductor Josephson junction.Moreover,the critical current is also studied and we show that the point of the discontinuity in the critical current curve is corresponding to the 0-7r transition point.