Publications
The Ground State Electronic Energy of Benzene
We report on the findings of a blind challenge devoted to determining the frozen-core, full configuration interaction (FCI) ground-state energy of the benzene molecule in a standard correlation-consistent basis set of double-ζ quality. As a broad international endeavor, our suite of wave function-based correlation methods collectively represents a diverse view of the high-accuracy repertoire offered by modern electronic structure theory.
Manipulation of the van der Waals Magnet Cr2Ge2Te6 by Spin–Orbit Torques
We report measurements of current-induced thermoelectric and spin-orbit torque effects within devices in which multilayers of the semiconducting two-dimensional van der Waals magnet Cr2Ge2Te6 (CGT) are integrated with Pt and Ta metal overlayers. We show that the magnetic orientation of the CGT can be detected accurately either electrically (using an anomalous Hall effect) or optically (using magnetic circular dichroism) with good consistency.
Direct Visualization of Trimerized States in 1T−TaTe2
Transition-metal dichalcogenides containing tellurium anions show remarkable charge-lattice modulated structures and prominent interlayer character. Using cryogenic scanning transmission electron microscopy (STEM), we map the atomic-scale structures of the high temperature (HT) and low temperature (LT) modulated phases in 1T'-TaTe2. At HT, we directly show in-plane metal distortions which form trimerized clusters and staggered, three-layer stacking.
Electrical switching of valley polarization in monolayer semiconductors
Achieving on-demand control of the valley degree of freedom is essential for valley-based information science and technology. Optical and magnetic control of the valley degree of freedom in monolayer transition-metal dichalcogenide (TMD) semiconductors has been studied extensively. However, electrical control of the valley polarization has remained a challenge. Here we demonstrate switching of the valley polarization in monolayer WSe2 by electrical gating. This is achieved by coupling a WSe2 monolayer to a two-dimensional (2D) layered magnetic insulator CrI3.
Establishing strongly-coupled 3D AdS quantum gravity with Ising dual using all-genus partition functions
Abstract We study 3D pure Einstein quantum gravity with negative cosmological constant, in the regime where the AdS radius l is of the order of the Planck scale. Specifically, when the Brown-Henneaux central charge c = 3l/2GN (GN is the 3D Newton constant) equals c = 1/2, we establish duality between 3D gravity and 2D Ising conformal field theory by matching gravity and conformal field theory partition functions for AdS spacetimes with general asymptotic boundaries. This duality was suggested by a genus-one calculation of Castro et al. [Phys. Rev. D85 (2012) 024032].
Fabrication of Injectable Micro-Scale Opto- Electronically Transduced Electrodes (MOTEs) for Physiological Monitoring
In vivo, chronic neural recording is critical to understand the nervous system, while a tetherless, miniaturized recording unit can render such recording minimally invasive. We present a tetherless, injectable micro-scale opto-electronically transduced electrode (MOTE) that is ∼ 60μ m × 30μ m × 330μ m, the smallest neural recording unit to date. The MOTE consists of an AlGaAs micro-scale light emitting diode (μ LED) heterogeneously integrated on top of conventional 180nm complementary metal-oxide-semiconductor (CMOS) circuit.
The 2021 quantum materials roadmap
In recent years, the notion of ‘Quantum Materials’ has emerged as a powerful unifying concept across diverse fields of science and engineering, from condensed-matter and coldatom physics to materials science and quantum computing.
Almost exact energies for the Gaussian-2 set with the semistochastic heat-bath configuration interaction method
The recently developed semistochastic heat-bath configuration interaction (SHCI) method is a systematically improvable selected configuration interaction plus perturbation theory method capable of giving essentially exact energies for larger systems than is possible with other such methods. We compute SHCI atomization energies for 55 molecules that have been used as a test set in prior studies because their atomization energies are known from experiment.
Thermal transport of helium-3 in a strongly confining channel
The investigation of transport properties in normal liquid helium-3 and its topological superfluid phases provides insights into related phenomena in electron fluids, topological materials, and putative topological superconductors. It relies on the measurement of mass, heat, and spin currents, due to system neutrality. Of particular interest is transport in strongly confining channels of height approaching the superfluid coherence length, to enhance the relative contribution of surface excitations, and suppress hydrodynamic counterflow.
Deconfined metal-insulator transitions in quantum Hall bilayers
We propose that quantum Hall bilayers in the presence of a periodic potential at the scale of the magnetic length can host examples of a deconfined metal-insulator transition (DMIT), where a Fermi-liquid (FL) metal with a generic electronic Fermi surface evolves into a gapped insulator (or an insulator with Goldstone modes) through a continuous quantum phase transition. The transition can be accessed by tuning a single parameter, and its universal critical properties can be understood using a controlled framework.