Publications
Interfacial engineering of a ZnO electron transporting layer using self-Assembled monolayers for high performance and stable perovskite solar cells
We developed perovskite solar cells (PSCs) with a ZnO electron-Transporting layer (ETL) of which the surface was passivated with methoxybenzoic acid self-Assembled monolayers (SAMs). The self-Assembled monolayer (SAM) simultaneously improved the photovoltaic performance and device stability.
Magneto-Memristive Switching in a 2D Layer Antiferromagnet
Memristive devices whose resistance can be hysteretically switched by electric field or current are intensely pursued both for fundamental interest as well as potential applications in neuromorphic computing and phase-change memory. When the underlying material exhibits additional charge or spin order, the resistive states can be directly coupled, further allowing electrical control of the collective phases. The observation of abrupt, memristive switching of tunneling current in nanoscale junctions of ultrathin CrI3, a natural layer antiferromagnet, is reported here.
Why Traditional Labs Fail, and What We Can Do About It
Science is, at its core, an empirical discipline: Theories must coordinate with evidence obtained through systematic, scientific investigations. Learning science involves learning how science is done, not just what science has found, and so nearly every introductory college science course has an associated laboratory component. The value of these labs, however, has often been called into question, particularly when considering concerns about the associated space, time, equipment, and personnel needs.
Wrapping of Microparticles by Floppy Lipid Vesicles
Role of correlations in determining the Van Hove strain in Sr2 RuO4
Uniaxial pressure applied along a Ru-O-Ru bond direction induces an elliptical distortion of the largest Fermi surface of Sr2RuO4, eventually causing a Fermi surface topological transition, also known as a Lifshitz transition, into an open Fermi surface. There are various anomalies in low-temperature properties associated with this transition, including maxima in the superconducting critical temperature and in resistivity.
Imaging uncompensated moments and exchange-biased emergent ferromagnetism in FeRh thin films
Uncompensated moments (UMs) in antiferromagnets are responsible for exchange bias in antiferromagnet/ ferromagnet heterostructures; however, they are difficult to directly detect because any signal they contribute is typically overwhelmed by the ferromagnetic layer. We use magnetothermal microscopy to image micron-scale uncompensated moments in thin films of FeRh, a room-temperature antiferromagnet that exhibits a first-order phase transition to a ferromagnetic (FM) state near 400 K.
Fractionalized pair density wave in the pseudogap phase of cuprate superconductors
The mysterious pseudogap (PG) phase of cuprate superconductors has been the subject of intense investigation over the last 30 years, but without a clear agreement about its origin. Owing to a recent observation in Raman spectroscopy, of a precursor in the charge channel, on top of the well known fact of a precursor in the superconducting channel, we present here a novel idea: The PG is formed through a Higgs mechanism, where two kinds of preformed pairs, in the particle-particle and particle-hole channels, become entangled through a freezing of their global phase.
Magnetic handshake materials as a scale-invariant platform for programmed self-assembly
Programmable self-assembly of smart, digital, and structurally complex materials from simple components at size scales from the macro to the nano remains a long-standing goal of material science. Here, we introduce a platform based on magnetic encoding of information to drive programmable self-assembly that works across length scales. Our building blocks consist of panels with different patterns of magnetic dipoles that are capable of specific binding.
A New method for computing particle collisions in Navier-Stokes flows
Particle collisions in fluids are ubiquitous, but to compute the collision dynamics in a Navier-Stokes flow remains challenging. In addition to capturing the two-way coupling between the fluid and the particles, a key difficulty is to resolve the collision dynamics mediated by the flow. The gap between particles during collision is minuscule. This introduces a small length scale which needs to be resolved simultaneously with the flow at the large scale.
Dirac fermions and possible weak antilocalization in LaCuSb2
Layered heavy-metal square-lattice compounds have recently emerged as potential Dirac fermion materials due to bonding within those sublattices. We report quantum transport and spectroscopic data on the layered Sb square-lattice material LaCuSb2. Linearly dispersing band crossings, necessary to generate Dirac fermions, are experimentally observed in the electronic band structure observed using angle-resolved photoemission spectroscopy, along with a quasi-two-dimensional Fermi surface.