Details

Autor(en) / Beteiligte

• Ayani, Cosme G
• Calleja, Fabian
• Ibarburu, Ivan M
• Casado Aguilar, Pablo
• Nazriq, Nana K. M
• Yamada, Toyo K
• Garnica, Manuela
• Vázquez de Parga, Amadeo L
• Miranda, Rodolfo

Titel

Switchable molecular functionalization of an STM tip: from a Yu-Shiba-Rusinov Tip to a Kondo tip

Ist Teil von

• Nanoscale, 2022-10, Vol.14 (4), p.15111-15118

Ort / Verlag

Cambridge: Royal Society of Chemistry

Erscheinungsjahr

2022

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• In this work we fabricate and characterize a functionalized superconducting (SC) Nb tip of a scanning tunnelling microscope (STM). The tip is functionalized with a Tetracyanoquinodimethane molecule (TCNQ) that accepts charge from the tip and develops a magnetic moment. As a consequence, in scanning tunnelling spectroscopy (STS), sharp, bias symmetric sub-gap states identified as Yu-Shiba-Rusinov (YSR) bound states appear against the featureless density of states of a metallic graphene on Ir(111) sample. Although the coupling regime of the magnetic impurity with the SC tip depends on the initial absorption configuration of the molecule, the interaction strength between the SC tip and the charged TCNQ molecule can be reversibly controlled by tuning the tip-sample distance. The controlled transition from one coupling regime to the other allows us to verify the relation between the energy scales of the two competing many-body effects for the functionalized tip. Quenching the SC state of the Nb tip with a magnetic field switches abruptly from a tip dominated by the YSR bound states to a Kondo tip. A Niobium superconducting STM tip is fuctionalised with an electron acceptor molecule, showing the corresponding Yu-Shiba-Rusinov (YSR) states in STS. Applying an external magnetic field allows the controlled switching from a YSR tip to a Kondo tip.