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@ARTICLE{Costi:865783,
author = {Costi, Theodoulos},
title = {{M}agnetic field dependence of the thermopower of
{K}ondo-correlated quantum dots: {C}omparison with
experiment},
journal = {Physical review / B},
volume = {100},
number = {15},
issn = {2469-9950},
address = {Woodbury, NY},
publisher = {Inst.},
reportid = {FZJ-2019-05091},
pages = {155126},
year = {2019},
abstract = {Signatures of the Kondo effect in the electrical
conductance of strongly correlated quantum dots are well
understood both experimentally and theoretically, while
those in the thermopower have been the subject of recent
interest, both theoretically and experimentally. Here, we
extend theoretical work [T. A. Costi, Phys. Rev. B 100,
161106 (2019)] on the field-dependent thermopower of such
systems to the mixed valence and empty orbital regimes, and
carry out calculations in order to address a recent
experiment on the field-dependent thermoelectric response of
Kondo-correlated quantum dots [A. Svilans et al., Phys. Rev.
Lett. 121, 206801 (2018)]. In addition to the sign changes
in the thermopower at temperatures T1(B) and T2(B) (present
also for B=0) in the Kondo regime, an additional sign change
was found [T. A. Costi, Phys. Rev. B (to be published)] at a
temperature T0(B)<T1(B)<T2(B) for fields exceeding a
gate-voltage-dependent value B0, where B0 is comparable to,
but larger than, the field Bc at which the Kondo resonance
splits. We describe the evolution of the Kondo-induced sign
changes in the thermopower at temperatures T0(B),T1(B), and
T2(B) with magnetic field and gate voltage from the Kondo
regime to the mixed valence and empty orbital regimes and
show that these temperatures merge to the single temperature
T0(B) upon entry into the mixed valence regime. By carrying
out detailed numerical renormalization group calculations
for the above quantities, using appropriate experimental
parameters, we address a recent experiment which measures
the field-dependent thermoelectric response of InAs quantum
dots exhibiting the Kondo effect [A. Svilans et al., Phys.
Rev. Lett. 121, 206801 (2018)]. This allows us to understand
the overall trends in the measured field- and
temperature-dependent thermoelectric response as a function
of gate voltage. In addition, we determine which signatures
of the Kondo effect [sign changes at T0(B),T1(B), and T2(B)]
have been observed in this experiment, and find that while
the Kondo-induced signature at T1(B) is indeed measured in
the data, the signature at T0(B) can only be observed by
carrying out further measurements at a lower temperature. In
addition, the less interesting (high-temperature) signature
at T2(B)≳Γ, where Γ is the electron tunneling rate onto
the dot, is found to lie above the highest temperature in
the experiment, and was therefore not accessed. Our
calculations provide a useful framework for interpreting
future experiments on direct measurements of the thermopower
of Kondo-correlated quantum dots in the presence of finite
magnetic fields, e.g., by extending zero-field measurements
of the thermopower [B. Dutta et al., Nano Lett. 19, 506
(2019).] to finite magnetic fields.},
cin = {IAS-3 / JARA-HPC},
ddc = {530},
cid = {I:(DE-Juel1)IAS-3-20090406 / $I:(DE-82)080012_20140620$},
pnm = {142 - Controlling Spin-Based Phenomena (POF3-142) /
Application of the (time-dependent) numerical
renormalization group approach to thermoelectric properties
of (driven) quantum dots and to time-resolved spectroscopy
of correlated materials $(jiff23_20181101)$},
pid = {G:(DE-HGF)POF3-142 / $G:(DE-Juel1)jiff23_20181101$},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000490168200002},
doi = {10.1103/PhysRevB.100.155126},
url = {https://juser.fz-juelich.de/record/865783},
}