Ground-state spin blockade in a single-molecule junction

Abstract

It is known that the quantum-mechanical ground state of a nano-scale junction has a significant impact on its electrical transport properties. This becomes particularly important in transistors consisting of a single molecule. Due to strong electron-electron interactions and the possibility to access ground states with high spins, these systems are eligible hosts of a current-blockade phenomenon called ground-state spin blockade. This effect arises from the inability of a charge carrier to account for the spin difference required to enter the junction, as that process would violate the spin selection rules. Here, we present a direct experimental demonstration of ground-state spin blockade in a high-spin single-molecule transistor. The measured transport characteristics of this device exhibit a complete suppression of resonant transport due to a ground-state spin difference of 3/2 between subsequent charge states. Strikingly, the blockade can be reversibly lifted by driving the system through a magnetic ground-state transition in one charge state, using the tunability offered by both magnetic and electric fields.

References in corpus (5)

• Majorana bound states in a coupled quantum-dot hybrid-nanowire system
• Franck-Condon blockade and giant Fano factors in transport through single molecules
• Franck-Condon blockade in suspended carbon nanotube quantum dots
• Pauli-Spin-Blockade Transport through a Silicon Double Quantum Dot
• Finite-bias conductance anomalies at a singlet-triplet crossing