About

Professor Christopher Gutiérrez is an Assistant Professor in the UCLA Department of Physics & Astronomy. He holds a PhD from Columbia University, Department of Physics. His research involves quantum matter, as indicated by his role in the Quantum Matter Design Studio. The page features an image of him performing careful surgery to repair the ultra-thin coaxial wire that carries the quantum tunneling current in a microscope, suggesting his hands-on involvement in experimental quantum physics. His team includes graduate students, undergraduate students, and support staff, all working under his guidance to explore various aspects of quantum matter. He can be contacted via email at gutierrez@physics.ucla.edu for research inquiries.

Research topics

• Condensed matter physics
• Physics
• Quantum mechanics
• Molecular physics
• Materials science
• Nanotechnology
• Chemical physics

Selected publications

• Mapping the three-dimensional fermiology of the triangular lattice magnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>EuAg</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mi>Sb</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>

  Physical review. B./Physical review. B · 2025-02-19 · 1 citations

  articleOpen access

  Magnetic materials that allow for the mapping of all Fermi surfaces to fully capture the interplay between magnetism and electronic structure are rare. The authors elucidate here the fermiology of antiferromagnetic EuAg${}_{4}$Sb${}_{2}$ through quantum oscillations, capturing full sets of spin-split Fermi pockets in the polarized ferromagnetic state. These results show good agreement with first-principles calculations and ARPES data. Temperature-dependent changes in the size and shape of the small hourglass pockets, but not the large ones, highlight that variations in exchange splitting, driven by changes in magnetic moment, primarily affect the small pockets without significantly altering the overall electronic structure in this compound.

  PublisherOA PDFDOI

• Mapping the three-dimensional fermiology of the triangular lattice magnet EuAg$_4$Sb$_2$

  ArXiv.org · 2025-01-17

  preprintOpen access

  In this paper, we report the temperature-field phase diagram as well as present a comprehensive study of the electronic structure and three-dimensional fermiology of the triangular-lattice magnet EuAg$_4$Sb$_2$, utilizing quantum oscillation measurements, angle-resolved photoemission spectroscopy and first-principles calculations. The complex magnetic phase diagram of EuAg$_4$Sb$_2$ highlights many transitions through nontrivial AFM states. Shubnikov-de Haas and de Haas-van Alphen oscillations were observed in the polarized ferromagnetic state of EuAg$_4$Sb$_2$, revealing three pairs of distinct spin-split frequency branches with small effective masses. A comparison of the angle-dependent oscillation data with first-principles calculations in the ferromagnetic state and angle-resolved photoemission spectra shows good agreement, identifying tubular hole pockets and hourglass-shaped hole pockets at the Brillouin zone center, as well as diamond-shaped electron pockets at the zone boundary. As the temperature increases, the frequency branches of the tiny hourglass pockets evolve into a more cylindrical shape, while the larger pockets remain unchanged. This highlights that variations in exchange splitting, driven by changes in the magnetic moment, primarily impact the small Fermi pockets without significantly altering the overall band structure. This is consistent with first-principles calculations, which show minimal changes near the Fermi level across ferromagnetic and simple antiferromagnetic states or under varying on-site Coulomb repulsion.

  PublisherOA PDFDOI

• PyAtoms: An interactive tool for simulating atomic scanning tunneling microscopy images of 2D materials, moiré systems and superlattices

  arXiv (Cornell University) · 2024-12-24

  preprintOpen accessSenior author

  We present PyAtoms, an interactive open-source software that rapidly simulates atomic-scale scanning tunneling microscopy (STM) and other scanning probe microscopy (SPM) images of two-dimensional (2D) layered materials, moiré systems, and superlattices. Rooted in a Fourier-space description of ideal atomic lattice images, PyAtoms is a Python-based graphical user interface (GUI) with robust capabilities for tuning lattice parameters (lattice constants, strain, number of layers, twist angles) and STM imaging parameters (pixels, scan size, scan angle) and provides time estimates for spectroscopic measurements. These capabilities allow users to efficiently plan time-consuming STM experiments. We provide an overview of PyAtoms' current features, describe its underlying mathematical principles, and then demonstrate simulations of several 2D materials including graphene with variable sublattice asymmetry, twisted tri-layer graphene moiré systems, and several charge- and bond-density wave systems.

  PublisherOA PDFDOI

• Geometric interference in a high-mobility graphene annulus <i>p-n</i> junction device

  Physical review. B./Physical review. B · 2022-01-10 · 3 citations

  articleOpen access

  The emergence of interference is observed in the resistance of a graphene annulus p-n junction device as a result of applying two separate gate voltages. The observed resistance patterns are carefully inspected, and it is determined that the position of the peaks resulting from those patterns is independent of temperature and magnetic field. Furthermore, these patterns are not attributable to Aharonov-Bohm oscillations, Fabry-P\'erot interference at the junction, or moir\'e potentials. The device data are compared with those of another device fabricated with a traditional Hall bar geometry, as well as with quantum transport simulation data. Since the two devices are of different topological classes, the subtle differences observed in the corresponding measured data indicate that the most likely source of the observed geometric interference patterns is quantum scarring.

  PublisherOA PDFDOI

• Ubiquitous defect-induced density wave instability in monolayer graphene

  Science Advances · 2022 · 37 citations

  • Condensed matter physics
  • Materials science
  • Molecular physics

  Quantum materials are notoriously sensitive to their environments, where small perturbations can tip a system toward one of several competing ground states. Graphene hosts a rich assortment of such competing phases, including a bond density wave instability ("Kekulé distortion") that couples electrons at the K/K' valleys and breaks the lattice symmetry. Here, we report observations of a ubiquitous Kekulé distortion across multiple graphene systems. We show that extremely dilute concentrations of surface atoms (less than three adsorbed atoms every 1000 graphene unit cells) can self-assemble and trigger the onset of a global Kekulé density wave phase. Combining complementary momentum-sensitive angle-resolved photoemission spectroscopy (ARPES) and low-energy electron diffraction (LEED) measurements, we confirm the presence of this density wave phase and observe the opening of an energy gap. Our results reveal an unexpected sensitivity of the graphene lattice to dilute surface disorder and show that adsorbed atoms offer an attractive route toward designing novel phases in two-dimensional materials.

  PublisherOA PDFDOI

• Shining a Light on Chiral Symmetry Breaking in Graphene

  Physics · 2021-05-19 · 1 citations

  articleOpen access1st authorCorresponding

  Shining a Light on

  PublisherOA PDFDOI

• Atomic Engineering of Monolayer Graphene: Inducing Kekulé Bond Order by Adatom Deposition

  Bulletin of the American Physical Society · 2020-03-05

  article
  Publisher

• Tuning single-electron charging and interactions between compressible Landau level islands in graphene

  Physical review. B./Physical review. B · 2020 · 21 citations

  • Physics
  • Condensed matter physics
  • Quantum mechanics

  Interacting and tunable quantum dots (QDs) have been extensively exploited in condensed matter physics and quantum information science. Using a low-temperature scanning tunneling microscope (STM), we both create and directly image a new type of coupled QD system in graphene, a highly interacting quantum relativistic system with tunable density. Using detailed scanning tunneling spectroscopy (STS) measurements, we show that Landau quantization inside a potential well enables novel electron confinement via the incompressible strips between partially filled Landau levels (LLs), forming isolated and concentric LL QDs. By changing the charge density and the magnetic field we can tune continuously between single- and double-concentric LL QD systems within the same potential well. In the concentric QD regime, single-electron charging peaks of the two dots intersect, displaying a characteristic avoidance pattern. At moderate fields, we observe an unconventional avoidance pattern that differs significantly from that observed in capacitively coupled double-QD systems. We find that we can reproduce in detail this anomalous avoidance pattern within the framework of the electrostatic double-QD model by replacing the capacitive interdot coupling with a phenomenological charge-counting system in which charges in the inner concentric dot are counted in the total charge of both islands. The emergence of such strange forms of interdot coupling in a single potential well, together with the ease of producing such charge pockets in graphene and other two-dimensional (2D) materials, reveals an intriguing testbed for the confinement of 2D electrons in customizable potentials.

  PublisherOA PDFDOI

• Strained-induced Landau levels in momentum space

  Bulletin of the American Physical Society · 2019-03-07

  article
  Publisher

• Writable and tunable Landau level quantum dots in graphene devices

  Bulletin of the American Physical Society · 2019-03-04

  article
  Publisher

Frequent coauthors

• Fereshte Ghahari

  33 shared

• Daniel Walkup

  Physical Measurement Laboratory

  32 shared

• Joseph A. Stroscio

  24 shared

• Nikolai B. Zhitenev

  23 shared

• Abhay N. Pasupathy

  Columbia University

  19 shared

• Son T. Le

  17 shared

• Takashi Taniguchi

  14 shared

• Kenji Watanabe

  National Institute for Materials Science

  14 shared

Labs

• Quantum Matter Design StudioPI

Education

• Ph. D, Physics

  Columbia University

  2015

Awards & honors

• Government Scholarship to Study Abroad from the Ministry of…