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We report on ground- and excited state transport through an electrostatically defined few-hole quantum dot in bilayer graphene in both parallel and perpendicular applied magnetic fields. A remarkably clear level scheme for the two-particle…

Mesoscale and Nanoscale Physics · Physics 2019-07-17 A. Kurzmann , M. Eich , H. Overweg , M. Mangold , F. Herman , P. Rickhaus , R. Pisoni , Y. Lee , R. Garreis , C. Tong , K. Watanabe , T. Taniguchi , K. Ensslin , T. Ihn

We perform an excited state spectroscopy analysis of a silicon corner dot in a nanowire field-effect transistor to assess the electric field tunability of the valley splitting. First, we demonstrate a back-gate-controlled transition between…

We examine a graphene quantum dot formed by combining an electric and a uniform magnetic field. The electric field creates a smooth quantum well potential while the magnetic field induces an exponential tail to the dot states. The states…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 G. Giavaras , Franco Nori

Single spins in the solid-state offer a unique opportunity to store and manipulate quantum information, and to perform quantum-enhanced sensing of local fields and charges. Optical control of these systems using techniques developed in…

Mesoscale and Nanoscale Physics · Physics 2013-02-28 Anthony J. Bennett , Matthew A. Pooley , Yameng Cao , Niklas Sköld , Ian Farrer , David A. Ritchie , Andrew J. Shields

At the center of quantum computing1 realization is the physical implementation of qubits - two-state quantum information units. The rise of graphene2 has opened a new door to the implementation. Because graphene electrons simulate…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 G. Y. Wu , N. -Y. Lue , L. Chang

Valley splitting is a key figure of silicon-based spin qubits. Quantum dots in Si/SiGe heterostructures reportedly suffer from a relatively low valley splitting, limiting the operation temperature and the scalability of such qubit devices.…

Understanding how the electron spin is coupled to orbital degrees of freedom, such as a valley degree of freedom in solid-state systems is central to applications in spin-based electronics and quantum computation. Recent developments in the…

Bilayer graphene (BLG)-based quantum devices represent a promising platform for emerging technologies, such as quantum computing and spintronics. However, their intrinsically weak spin-orbit coupling (SOC) complicates spin and valley…

This is a review on graphene quantum dots and their use as a host for spin qubits. We discuss the advantages but also the challenges to use graphene quantum dots for spin qubits as compared to the more standard materials like GaAs. We start…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 Patrik Recher , Bjoern Trauzettel

Graphene quantum dots provide promising platforms for hosting spin, valley, or spin-valley qubits. Taking advantage of the electrically generated band gap and the ambipolar nature, high-quality quantum dots can be defined in bilayer…

Mesoscale and Nanoscale Physics · Physics 2023-11-02 Fang-Ming Jing , Guo-Quan Qin , Zhuo-Zhi Zhang , Xiang-Xiang Song , Guo-Ping Guo

We determine the optical properties of gated bilayer graphene quantum dots with trigonal warping (TW) of single-particle energy spectra. The lateral structure of metallic gates confines electrons and holes in a quantum dot (QD)…

Mesoscale and Nanoscale Physics · Physics 2025-06-03 Matthew Albert , Daniel Miravet , Yasser Saleem , Katarzyna Sadecka , Marek Korkusinski , Gabriel Bester , Pawel Hawrylak

The valley degree of freedom in 2D materials can be manipulated for low-dissipation quantum electronics called valleytronics. At the boundary between two regions of bilayer graphene with different atomic or electrostatic configuration,…

Mesoscale and Nanoscale Physics · Physics 2024-04-03 Konstantin Davydov , Xi Zhang , Wei Ren , Matthew Coles , Logan Kline , Bryan Zucker , Kenji Watanabe , Takashi Taniguchi , Ke Wang

Trapping electrons in quantum dots and controlling their collective quantum states is crucial for converting semiconductor structures into bits of quantum information processing. Here, we study single- and two-particle states in quantum…

Mesoscale and Nanoscale Physics · Physics 2020-07-01 Angelika Knothe , Vladimir Fal'ko

We report a large g-factor tunability of a single hole spin in an InGaAs quantum dot via an electric field. The magnetic field lies in the in-plane direction x, the direction required for a coherent hole spin. The electrical field lies…

The tuneability and control of quantum nanostructures in two-dimensional materials offer promising perspectives for their use in future electronics. It is hence necessary to analyze quantum transport in such nanostructures. Material…

Mesoscale and Nanoscale Physics · Physics 2022-11-01 Angelika Knothe , Leonid I. Glazman , Vladimir I. Fal'ko

The intrinsic valley degree of freedom makes bilayer graphene (BLG) a unique platform for semiconductor qubits. The single-carrier quantum dot (QD) ground state exhibits a two-fold degeneracy, where the two states that constitute a Kramers…

Graphene double quantum open the possibility to use charge or spin degrees of freedom for storing and manipulating quantum information in this new electronic material. However, impurities and edge disorders in etched graphene…

Mesoscale and Nanoscale Physics · Physics 2014-06-18 Da Wei , Hai-Ou Li , Gang Cao , Gang Luo , Zhi-Xiong Zheng , Tao Tu , Ming Xiao , Guang-Can Guo , Hong-Wen Jiang , Guo-Ping Guo

We have measured a graphene double quantum dot device with multiple electrostatic gates that are used to enhance control to investigate it. At low temperatures the transport measurements reveal honeycomb charge stability diagrams which can…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 L. J. Wang , H. O. Li , Z. Su , T. Tu , G. Cao , C. Zhou , X. J. Hao , G. C. Guo , G. P. Guo

Pauli blockade is a fundamental quantum phenomenon that also serves as a powerful tool for qubit manipulation and read-out. While most systems exhibit a simple even-odd pattern of double-dot Pauli spin blockade due to the preferred singlet…

Mesoscale and Nanoscale Physics · Physics 2024-04-11 Chuyao Tong , Annika Kurzmann , Rebekka Garreis , Kenji Watanabe , Takashi Taniguchi , Thomas Ihn , Klaus Ensslin

Topological properties of electronic states in multivalley two-dimensional materials, such as mono- and bilayer graphene, or thin films of rhombohedral graphite, give rise to various unusual magneto-transport regimes. Here, we investigate…

Mesoscale and Nanoscale Physics · Physics 2022-12-22 Christian Moulsdale , Angelika Knothe , Vladimir Fal'ko