TY - JOUR
T1 - Magnetically Tuned Kondo Effect in a Molecular Double Quantum Dot
T2 - Role of the Anisotropic Exchange
AU - Zalom, Peter
AU - De Bruijckere, Joeri
AU - Gaudenzi, Rocco
AU - Van Der Zant, Herre S.J.
AU - Novotný, Tomáš
AU - Korytár, Richard
N1 - Accepted Author Manuscript
PY - 2019
Y1 - 2019
N2 - We investigate theoretically and experimentally the singlet-triplet Kondo effect induced by a magnetic field in a molecular junction. Temperature-dependent conductance, G(T), is calculated by the numerical renormalization group, showing a strong imprint of the relevant low-energy scales, such as the Kondo temperature, exchange, and singlet-triplet splitting. We demonstrate the stability of the singlet-triplet Kondo effect against weak spin anisotropy, modeled by an anisotropic exchange. Moderate spin anisotropy manifests itself by lowering the Kondo plateaus, causing the G(T) to deviate from a standard temperature dependence, expected for a spin-half Kondo effect. We propose this scenario as an explanation for anomalous G(T), measured in an organic diradical molecule coupled to gold contacts. We uncover certain new aspects of the singlet-triplet Kondo effect, such as coexistence of spin-polarization on the molecule with Kondo screening and nonperturbative parametric dependence of an effective magnetic field induced by the leads.
AB - We investigate theoretically and experimentally the singlet-triplet Kondo effect induced by a magnetic field in a molecular junction. Temperature-dependent conductance, G(T), is calculated by the numerical renormalization group, showing a strong imprint of the relevant low-energy scales, such as the Kondo temperature, exchange, and singlet-triplet splitting. We demonstrate the stability of the singlet-triplet Kondo effect against weak spin anisotropy, modeled by an anisotropic exchange. Moderate spin anisotropy manifests itself by lowering the Kondo plateaus, causing the G(T) to deviate from a standard temperature dependence, expected for a spin-half Kondo effect. We propose this scenario as an explanation for anomalous G(T), measured in an organic diradical molecule coupled to gold contacts. We uncover certain new aspects of the singlet-triplet Kondo effect, such as coexistence of spin-polarization on the molecule with Kondo screening and nonperturbative parametric dependence of an effective magnetic field induced by the leads.
UR - http://www.scopus.com/inward/record.url?scp=85065620937&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.9b00783
DO - 10.1021/acs.jpcc.9b00783
M3 - Article
AN - SCOPUS:85065620937
VL - 123
SP - 11917
EP - 11925
JO - The Journal of Physical Chemistry C
JF - The Journal of Physical Chemistry C
SN - 1932-7455
IS - 18
ER -