Cryogen-free variable-temperature Kelvin probe force microscopy for probing local chemical potential in a graphene heterostructure

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Main Authors: Lee, Namkyung, Jung, Seungwon, Jang, Baeksan, Ha, Sangwook, Jang, Joonho
Format: Preprint
Published: 2025
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author Lee, Namkyung
Jung, Seungwon
Jang, Baeksan
Ha, Sangwook
Jang, Joonho
author_facet Lee, Namkyung
Jung, Seungwon
Jang, Baeksan
Ha, Sangwook
Jang, Joonho
contents We report the development of a variable-temperature Kelvin probe force microscopy (KPFM) system capable of stable and highly sensitive operation over a wide temperature range based on a GM-cooler-based cryogen-free cryostat. The system incorporates a custom-designed phase-locked loop and automatic gain control, along with passive vibration isolation, enabling precise measurements of local chemical potential even under cryogenic conditions. We demonstrate the performance of this setup by measuring hBN encapsulated monolayer graphene (MLG), revealing spatially resolved electronic inhomogeneities and charge puddles. Our measurements clearly capture temperature-dependent variations in the chemical potential near the charge neutrality point (CNP), consistent with the linear band dispersion of MLG and interaction-driven renormalization of Fermi velocity. This work highlights the robust sensitivity and stability of our system, making it a versatile local probe of quantum phases in van der Waals heterostructures.
format Preprint
id arxiv_https___arxiv_org_abs_2507_09976
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cryogen-free variable-temperature Kelvin probe force microscopy for probing local chemical potential in a graphene heterostructure
Lee, Namkyung
Jung, Seungwon
Jang, Baeksan
Ha, Sangwook
Jang, Joonho
Applied Physics
Mesoscale and Nanoscale Physics
We report the development of a variable-temperature Kelvin probe force microscopy (KPFM) system capable of stable and highly sensitive operation over a wide temperature range based on a GM-cooler-based cryogen-free cryostat. The system incorporates a custom-designed phase-locked loop and automatic gain control, along with passive vibration isolation, enabling precise measurements of local chemical potential even under cryogenic conditions. We demonstrate the performance of this setup by measuring hBN encapsulated monolayer graphene (MLG), revealing spatially resolved electronic inhomogeneities and charge puddles. Our measurements clearly capture temperature-dependent variations in the chemical potential near the charge neutrality point (CNP), consistent with the linear band dispersion of MLG and interaction-driven renormalization of Fermi velocity. This work highlights the robust sensitivity and stability of our system, making it a versatile local probe of quantum phases in van der Waals heterostructures.
title Cryogen-free variable-temperature Kelvin probe force microscopy for probing local chemical potential in a graphene heterostructure
topic Applied Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2507.09976