TY  - JOUR
AU  - Costi, T. A.
TI  - Magnetic field dependence of the thermopower of Kondo-correlated quantum dots
JO  - Physical review / B
VL  - 100
IS  - 16
SN  - 2469-9950
CY  - Woodbury, NY
PB  - Inst.
M1  - FZJ-2019-05090
SP  - 161106
PY  - 2019
AB  - Recent experiments have measured the signatures of the Kondo effect in the zero-field thermopower of strongly correlated quantum dots [Svilans et al., Phys. Rev. Lett. 121, 206801 (2018); Dutta et al., Nano Lett. 19, 506 (2019)]. They confirm the predicted Kondo-induced sign change in the thermopower, upon increasing the temperature through a gate-voltage dependent value T1≳TK, where TK is the Kondo temperature. Here, we use the numerical renormalization group (NRG) method to investigate the effect of a finite magnetic field B on the thermopower of such quantum dots. We show that, for fields B exceeding a gate-voltage dependent value B0, an additional sign change takes place in the Kondo regime at a temperature T0(B≥B0)>0 with T0<T1. The field B0 is comparable to, but larger than, the field Bc at which the zero-temperature spectral function splits in a magnetic field. The validity of the NRG results for B0 are checked by comparison with asymptotically exact higher-order Fermi-liquid calculations [Oguri and Hewson, Phys. Rev. B 97, 035435 (2018)]. Our calculations clarify the field-dependent signatures of the Kondo effect in the thermopower of Kondo-correlated quantum dots and explain the recently measured trends in the B-field dependence of the thermoelectric response of such systems
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000490169800001
DO  - DOI:10.1103/PhysRevB.100.161106
UR  - https://juser.fz-juelich.de/record/865782
ER  -