Tunable Wigner Molecules in a Germanium Quantum Dot

Fuente: arXiv
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Hauptverfasser: Yang, Chenggang, Lu, Jun, Wang, Hongzhang, Zeng, Jian, Bian, Wendong, Guo, Zhengshan, Li, Jiankun, Zhang, Yulei, Luo, Junwei, Pei, Tian
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Veröffentlicht: 2025
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author Yang, Chenggang
Lu, Jun
Wang, Hongzhang
Zeng, Jian
Bian, Wendong
Guo, Zhengshan
Li, Jiankun
Zhang, Yulei
Luo, Junwei
Pei, Tian
author_facet Yang, Chenggang
Lu, Jun
Wang, Hongzhang
Zeng, Jian
Bian, Wendong
Guo, Zhengshan
Li, Jiankun
Zhang, Yulei
Luo, Junwei
Pei, Tian
contents The interplay between Coulomb interactions and kinetic energy underlies many exotic phases in condensed matter physics. In a two-dimensional electronic system, If Coulomb interaction dominates over kinetic energy, electrons condense into a crystalline phase which is referred as Wigner crystal. This ordered state manifests as Wigner molecule for few electrons at the microscopic scale. Observation of Wigner molecules has been reported in quantum dot and moire superlattice systems. Here we demonstrate hole Wigner molecules can be formed in a gate-defined germanium quantum dot with high tunability. By varying voltages applied to the quantum dot device, we can precisely tune the hole density by either changing the hole occupancy or the quantum dot size. For densities smaller than a certain critical value, Coulomb interaction localizes individual holes into ordered lattice sites, forming a Wigner molecule. By increasing the densities, melting process from a Wigner molecule to Fermi liquid-like particles is observed. An intermediate configuration which indicates the coexistence of ordered structure and disordered structure can be formed within a narrow effective density range. Our results provide a new platform for further exploration of the microscopic feature of strong correlated physics and open an avenue to exploit the application of Wigner molecules for quantum information in a very promising spin qubit platform.
format Preprint
id arxiv_https___arxiv_org_abs_2510_01786
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Tunable Wigner Molecules in a Germanium Quantum Dot
Yang, Chenggang
Lu, Jun
Wang, Hongzhang
Zeng, Jian
Bian, Wendong
Guo, Zhengshan
Li, Jiankun
Zhang, Yulei
Luo, Junwei
Pei, Tian
Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
Quantum Physics
The interplay between Coulomb interactions and kinetic energy underlies many exotic phases in condensed matter physics. In a two-dimensional electronic system, If Coulomb interaction dominates over kinetic energy, electrons condense into a crystalline phase which is referred as Wigner crystal. This ordered state manifests as Wigner molecule for few electrons at the microscopic scale. Observation of Wigner molecules has been reported in quantum dot and moire superlattice systems. Here we demonstrate hole Wigner molecules can be formed in a gate-defined germanium quantum dot with high tunability. By varying voltages applied to the quantum dot device, we can precisely tune the hole density by either changing the hole occupancy or the quantum dot size. For densities smaller than a certain critical value, Coulomb interaction localizes individual holes into ordered lattice sites, forming a Wigner molecule. By increasing the densities, melting process from a Wigner molecule to Fermi liquid-like particles is observed. An intermediate configuration which indicates the coexistence of ordered structure and disordered structure can be formed within a narrow effective density range. Our results provide a new platform for further exploration of the microscopic feature of strong correlated physics and open an avenue to exploit the application of Wigner molecules for quantum information in a very promising spin qubit platform.
title Tunable Wigner Molecules in a Germanium Quantum Dot
topic Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2510.01786