@article{WOS:000656292200001,
 abstract = {Thermoelectric measurements have the potential to uncover the density of
states (DOSs) of low-dimensional materials. Here, we present the
anomalous thermoelectric behavior of monolayer graphene-nanowire (NW)
heterostructures, showing large oscillations as a function of the doping
concentration. Our devices consist of InAs NW and graphene vertical
heterostructures, which are electrically isolated by thin (similar to 10
nm) hexagonal boron nitride (hBN) layers. In contrast to conventional
thermoelectric measurements, where a heater is placed on one side of a
sample, we use the InAs NW (diameter similar to 50 nm) as a local heater
placed in the middle of the graphene channel. We measure the
thermoelectric voltage induced in graphene due to Joule heating in the
NW as a function of temperature (1.5-50 K) and carrier concentration.
The thermoelectric voltage in bilayer graphene (BLG)-NW heterostructures
shows sign change around the Dirac point, as predicted by Mott's
formula. In contrast, the thermoelectric voltage measured across
monolayer graphene (MLG)-NW heterostructures shows anomalous
large-amplitude oscillations around the Dirac point, not seen in the
Mott response derived from the electrical conductivity measured on the
same device. The anomalous oscillations are a signature of the modified
DOSs in MLG by the electrostatic potential of the NW, which is much
weaker in the NW-BLG devices. Thermal calculations of the
heterostructure stack show that the temperature gradient is dominant in
the graphene region underneath the NW, and thus sensitive to the
modified DOSs resulting in anomalous oscillations in the thermoelectric
voltage. Furthermore, with the application of a magnetic field, we
detect modifications in the DOSs due to the formation of Landau levels
in both MLG and BLG.},
 article-number = {345201},
 author = {Mitra, Richa and Ranjan Sahu, Manas and Sood, Aditya and Taniguchi,
Takashi and Watanabe, Kenji and Shtrikman, Hadas and Mukerjee, Subroto
and Sood, A. K. and Das, Anindya},
 doi = {10.1088/1361-6528/ac0191},
 eissn = {1361-6528},
 issn = {0957-4484},
 journal = {NANOTECHNOLOGY},
 month = {AUG 20},
 number = {34},
 orcid-numbers = {Mitra, Richa/0000-0001-8852-6645
Watanabe, Kenji/0000-0003-3701-8119},
 researcherid-numbers = {Watanabe, Kenji/H-2825-2011},
 title = {Anomalous thermopower oscillations in graphene-nanowire vertical
heterostructures},
 unique-id = {WOS:000656292200001},
 volume = {32},
 year = {2021}
}