Imaging Coulomb interactions and migrating Dirac cones in twisted graphene by local quantum oscillations

• URL: http://arxiv.org/abs/2407.10675v1
• Date: Mon, 15 Jul 2024 12:47:22 GMT
• Title: Imaging Coulomb interactions and migrating Dirac cones in twisted graphene by local quantum oscillations
• Authors: Matan Bocarsly, Indranil Roy, Vishal Bhardwaj, Matan Uzan, Patrick Ledwith, Gal Shavit, Nasrin Banu, Yaozhang Zhou, Yuri Myasoedov, Kenji Watanabe, Takashi Taniguchi, Yuval Oreg, Dan Parker, Yuval Ronen, Eli Zeldov,
• Abstract summary: We use a nanoscale scanning superconducting quantum interference device to image the local thermodynamic quantum oscillations in alternating-twist trilayer graphene at magnetic fields as low as 56 mT. We find that the charging self-energy due to occupied electronic states, is critical in explaining the high carrier density physics. At half-filling of the conduction flat band, we observe a Stoner-like symmetry breaking, suggesting that it is the most robust mechanism in the hierarchy of phase transitions.
• Score: 0.23191656838250044
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Flat band moir\'e graphene systems have emerged as a quintessential platform to investigate correlated phases of matter. A plethora of interaction-driven ground states have been proposed, and yet despite extensive experimental effort, there has been little direct evidence that distinguishes between the various phases, in particular near charge neutrality point. Here, we use a nanoscale scanning superconducting quantum interference device to image the local thermodynamic quantum oscillations in alternating-twist trilayer graphene at magnetic fields as low as 56 mT, which reveal ultrafine details of the density of states and of the renormalization of the single-particle band structure by Coulomb interactions. We find that the charging self-energy due to occupied electronic states, is critical in explaining the high carrier density physics. At half-filling of the conduction flat band, we observe a Stoner-like symmetry breaking, suggesting that it is the most robust mechanism in the hierarchy of phase transitions. On approaching charge neutrality, where the charging energy is negligible and exchange energy is dominant, we find the ground state to be a nematic semimetal which is favored over gapped states in the presence of heterostrain. In the revealed semimetallic phase, the flat-band Dirac cones migrate towards the mini-Brillouin zone center, spontaneously breaking the C_3 rotational symmetry. Our low-field local quantum oscillations technique presents an alluring avenue to explore the ground states of diverse strongly interacting van der Waals systems.

Related papers

• Longitudinal (curvature) couplings of an $N$-level qudit to a superconducting resonator at the adiabatic limit and beyond [0.0]
  We investigate the coupling between a multi-level system, or qudit, and a superconducting (SC) resonator's electromagnetic field. For the first time, we derive Hamiltonians describing the longitudinal multi-level interactions in a general dispersive regime. We provide examples illustrating the transition from adiabatic to dispersive coupling in different qubit systems.
  arXiv  Detail & Related papers  (2023-12-05T20:33:59Z)
• Dynamical correlations and order in magic-angle twisted bilayer graphene [0.272760415353533]
  We study the emergence of electronic correlations and long-range order in twisted bilayer graphene. Our findings provide a unified understanding of the most puzzling aspects of scanning tunneling spectroscopy, transport, and compressibility experiments.
  arXiv  Detail & Related papers  (2023-09-15T16:46:36Z)
• Cavity-induced switching between Bell-state textures in a quantum dot [0.0]
  We show how a simple theoretical model of this interplay at resonance predicts complex but measurable effects. New polariton states emerge that combine spin, relative modes, and radiation. We uncover novel topological effects involving highly correlated spin and charge density.
  arXiv  Detail & Related papers  (2023-08-17T01:31:36Z)
• Fragmented superconductivity in the Hubbard model as solitons in Ginzburg-Landau theory [58.720142291102135]
  Superconductivity and charge density waves are observed in close vicinity in strongly correlated materials. We investigate the nature of such an intertwined state of matter stabilized in the phase diagram of the elementary $t$-$tprime$-$U$ Hubbard model. We provide conclusive evidence that the macroscopic wave functions of the superconducting fragments are well-described by soliton solutions of a Ginzburg-Landau equation.
  arXiv  Detail & Related papers  (2023-07-21T18:00:07Z)
• Realization of a fractional quantum Hall state with ultracold atoms [0.0]
  Emblematic instances are fractional quantum Hall states, where the interplay of magnetic fields and strong interactions gives rise to fractionally charged quasi-particles. Here, we realize a fractional quantum Hall (FQH) state with ultracold atoms in an optical lattice.
  arXiv  Detail & Related papers  (2022-10-19T22:48:43Z)
• Formation of robust bound states of interacting microwave photons [148.37607455646454]
  One of the hallmarks of interacting systems is the formation of multi-particle bound states. We develop a high fidelity parameterizable fSim gate that implements the periodic quantum circuit of the spin-1/2 XXZ model. By placing microwave photons in adjacent qubit sites, we study the propagation of these excitations and observe their bound nature for up to 5 photons.
  arXiv  Detail & Related papers  (2022-06-10T17:52:29Z)
• Review on coherent quantum emitters in hexagonal boron nitride [91.3755431537592]
  I discuss the state-of-the-art of defect centers in hexagonal boron nitride with a focus on optically coherent defect centers. The spectral transition linewidth remains unusually narrow even at room temperature. The field is put into a broad perspective with impact on quantum technology such as quantum optics, quantum photonics as well as spin optomechanics.
  arXiv  Detail & Related papers  (2022-01-31T12:49:43Z)
• Cavity-mediated electron hopping in disordered quantum Hall systems [0.0]
  We show that the counter-rotating (anti-resonant) light-matter interaction produces an effective hopping between disordered eigenstates within the last occupied Landau band. We study such a cavity-mediated hopping mechanism in the dual presence of a random disordered potential.
  arXiv  Detail & Related papers  (2021-07-20T12:12:08Z)
• Bloch-Landau-Zener dynamics induced by a synthetic field in a photonic quantum walk [52.77024349608834]
  We realize a photonic quantum walk in the presence of a synthetic gauge field. We investigate intriguing system dynamics characterized by the interplay between Bloch oscillations and Landau-Zener transitions.
  arXiv  Detail & Related papers  (2020-11-11T16:35:41Z)
• A multiconfigurational study of the negatively charged nitrogen-vacancy center in diamond [55.58269472099399]
  Deep defects in wide band gap semiconductors have emerged as leading qubit candidates for realizing quantum sensing and information applications. Here we show that unlike single-particle treatments, the multiconfigurational quantum chemistry methods, traditionally reserved for atoms/molecules, accurately describe the many-body characteristics of the electronic states of these defect centers.
  arXiv  Detail & Related papers  (2020-08-24T01:49:54Z)
• Quantum decoherence by Coulomb interaction [58.720142291102135]
  We present an experimental study of the Coulomb-induced decoherence of free electrons in a superposition state in a biprism electron interferometer close to a semiconducting and metallic surface. The results will enable the determination and minimization of specific decoherence channels in the design of novel quantum instruments.
  arXiv  Detail & Related papers  (2020-01-17T04:11:44Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.