Current noises in a topological Josephson junction

• 来源期刊: 中国科学（物理学 力学 天文学）
• 年，卷（期）: 2018,（9）
• 页码范围: 75-81
• 页数: 7页
• 语种: 中文

摘要

We study the transport properties of a superconductor-quantum spin Hall insulator-superconductor Josephson junction both in the absence and in the presence of a DC bias voltage.As the system is predicted to host Majorana fermions at its interfaces,the Andreev bond states are supposed to exhibit a distinct 4π periodicity in the superconducting phase difference,namely the fractional Josephson effect.Using the non-equilibrium Green's function method,we calculate the current and the related current noise based on a tight-binding Hamiltonian.Our direct results show that the fractional Josephson effect can not be seen in equilibrium junctions.While in non-equilibrium junctions,this effect can be confirmed by the multiple Andreev reflections induced peaks of the non-equilibrium noise,which appear at discrete frequencies ω =neV with n being an integer number.