Quantum Materials

Home | Projects | Team | Publications | About

A quantum material defies classical explanation. It can be quantum due to strong correlation between electrons, topology, or reduced dimensionality. The confluence of multiple aspects can create difficult to anticipate novel quantum behaviors.

The quantum materials our group studies today may enable paradigm shifts in the technologies of the future, with wide ranging applications from electronics to photonics, and from neurology to quantum computing.

Superconductivity

High temperature and topological superconductivity are the next frontiers in superconducting research. Being among the most studied and challenging problems in condensed matter physics today, these materials bear many fascinating and unsolved mysteries, holding promise for a wide range of technological applications, from electrical power grid to novel sensors. While it is well known that the intriguing landscape of these superconductors is shaped by heterogeneity, whether heterogeneity is essential for driving novel quantum behaviors is still unknown. What are the roles of structural, orbital, nematic and magnetic fluctuations in generating high-Tc superconductivity? Are inhomogeneity and fractal reorganization key to emergence and to the complicated phenomenology of unconventional superconductors? How can topological superconductivity can be engineered by combination of layered materials? These are some of the mysteries our group is trying to solve by a combination of novel advanced tool and material design.

Cuprate Spin Textures

Spin-ARPES reveals an unexpected momentum space spin texture in high temperature superconductor Bi-2212.

Learn More Read paper

Pump-Probe ARPES

The Lanzara Group develops time resolved ARPES, a new technique to attack the problem of high-Tc superconductivity.

Learn More Read paper

Electron-Boson Coupling in Cuprates

Tr-ARPES uncovers dramatic changes in electron-boson coupling in the normal and superconducting states.

Learn More Read paper

Probing Pseudogap by Driving Change in Chemical Potential

By designing a new setup that allows to perform ARPES experiments under gating conditions, we enabled direct access to the doping-dependent electronic structure of graphene.
We discover that electronic correlations drives electron-hole symmetry breaking in graphene. Gate-tuning correlations provides new avenue to produce exotic phases in quantum materials.

Read Paper

Superconductivity

Confronting the challenge of achieving higher-Tc and topological superconductivity with ARPES

Low Dimensional Correlated Materials

Designing novel correlated phases at epitaxial interfaces

Disorder Engineering

Controlling material properties with or in the face of disorder

Topology & Symmetry

Levering the topology-symmetry connection to impart robust properties to materials

Low Dimensional Correlated Materials

The past few years have seen the emergence of correlation physics in reduced-dimensional systems where the behavior of electrons can be controlled by geometric effects, via the creation of Moire patterns through stacking and twisting of different atomic layers. By choice of the angle between the materials at the interface, or the lattice constant of the two materials, the electrons at the interface experience a beating between different lattices. Under the right conditions, this beating will restructure the electronic bands at low energy and dramatically change the essential material properties. We are exploring these incredibly rich low dimensional materials platforms, to design new topological, superconducting and magnetic ground states via a controlled assembly of different atomic layers spanning from semimetal graphene, semiconductors such as transition metal dichalcogenides, topological insulators and layered unconventional superconductors.

Tunable Electronics in Oxide Heteorstructures

Control of the valence electronics in 2D oxide heterostructures may provide an alternative to silicon in next century's electronics.

Learn More Read paper

Electron Localization in Moiré Superlattices

Nano-ARPES demonstrates band flattening and explores hybridization as contributor to superlattice physics in TMDCs.

Learn More Read paper

Correlation driven Symmetry Breaking in Graphene

By designing a new setup that allows to perform ARPES experiments under gating conditions, we enabled direct access to the doping-dependent electronic structure of graphene.
We discover that electronic correlations drive electron-hole symmetry breaking in graphene. Gate-tuning correlations provides new avenue to produce exotic phases in quantum materials.

Learn more Read Paper

Tunable Bandgaps in Graphene

Substrate induced gap opening paves a pathway towards graphene-based transistors.

Learn More Read paper

Screening and Interaction in Graphene

ARPES reveals subtle effects due to long range interactions in graphene.

Learn More Read paper

Topology and Symmetry

There is a direct connection between the symmetries a material obeys, and the topology of the electron wavefunctions: symmetries protect the wavefunction topology and resultant properties even in the presence of strong disorder. Our interests in this field span from , leveraging topology-symmetry connection to control the electronic and optical properties of quantum materials; to search for topological materials with localized surface states to stabilize novel superconducting andmagnetic phases; to reliably manipulate symmetry to control topology and electron behaviors.

Dirac Nodes in Prototype Semimetal BaAl4

ARPES finds nontrivial topology in BaAl4, a representative member of a larger material family, together with proximal Van Hove singularities.

Learn More Read paper

Spin-polarized Surface Resonances Accompanying Topological Surface State Formation.
This work shows what happens as topological insulators emerge through a phase transition from trivial materials. This new class of material holds the potential to revolutionize computing.

Learn more Read Paper

Surface State Photovoltage Effect in Topological Insulators

Polarized laser-ARPES photoemission from a topological insulator provides control of ejected electron spin.

Learn More Read paper

Disorder Engineering

Over the past century, scientists have relied on symmetry and crystalline order to classify states of matter, understand their hierarchy, and predict material behavior. However, some of the most fascinating exotic phenomena appears in extremely disordered materials and often amorphous materials present higher and performance than their ordered counterpart. This still present a puzzle today. Our goal is to understand what makes disorder and fractal reorganization essential in shaping the many ground states of quantum materials and what new emergent electronic orders can be realized in amorphous systems from the hyperuniformity of the amorphous atomic positions.

Topology in an amorphous film

The discovery of an amorphous TI uncovers an entire class of neglected topological phases outside the crystalline classification scheme.

Learn More Read paper

Coexistence of Order and Disorder in Graphite

Contrary to expectation, sharp quasiparticle dispersions are observable even in the face of strong disorder.

Learn More Read paper

Metal to Insulator Transition in Doped Graphene

In the presence of disordered molecular dopants, graphene undergoes a metal-insulator transition suitable for next generation electronics.

Learn More Read paper

Quantum Materials

Home | Projects | Team | Publications | About