Bio


We are engaged in theory and modeling of materials at the atomic scale. Our recent work has two primary directions:

1. Monolayer and few layer materials (i.e. graphene, MoS2) for electronics, NEMS, and energy applications.
2. Materials at conditions of high temperature, electromagnetic fields, and pressures, including dynamic or shock compression.

Recent research topics include piezoelectricity and phase change effects in monolayer materials. Past topics include THz radiation generation, energetic materials, and photonic crystals. We develop and utilize computational tools (molecular dynamics statistical methods, electronic structure, materials informatics approaches, etc.) and interact closely with experimentalists.

Academic Appointments


Honors & Awards


  • ONR Young Investigator Program Award (YIP), Office of Naval Research (2015)
  • NSF Career Award, NSF (2014)
  • Young Faculty Award, DARPA (2012)
  • Robert Noyce Faculty Scholar, Stanford University School of Engineering (2010-2013)
  • Ernest O. Lawrence Postdoctoral Fellow, Lawrence Livermore National Laboratory (2004 - 2007)

Professional Education


  • BS, Caltech, Applied Physics (1998)
  • PhD, MIT, Physics (2003)

2018-19 Courses


Stanford Advisees


All Publications


  • Machine Learning-Assisted Discovery of Solid Li-Ion Conducting Materials CHEMISTRY OF MATERIALS Sendek, A. D., Cubuk, E. D., Antoniuk, E. R., Cheon, G., Cui, Y., Reed, E. J. 2019; 31 (2): 342–52
  • ODE integration schemes for plane-wave real-time time-dependent density functional theory. The Journal of chemical physics Rehn, D. A., Shen, Y., Buchholz, M. E., Dubey, M., Namburu, R., Reed, E. J. 2019; 150 (1): 014101

    Abstract

    Integration schemes are implemented with a plane-wave basis in the context of real-time time-dependent density functional theory. Crank-Nicolson methods and three classes of explicit integration schemes are explored and assessed in terms of their accuracy and stability properties. Within the framework of plane-wave density functional theory, a graphene monolayer system is used to investigate the error, stability, and serial computational cost of these methods. The results indicate that Adams-Bashforth and Adams-Bashforth-Moulton methods of orders 4 and 5 outperform commonly used methods, including Crank-Nicolson and Runge-Kutta methods, in simulations where a relatively low error is desired. Parallel runtime scaling of the most competitive serial methods is presented, further demonstrating that the Adams-Bashforth and Adams-Bashforth-Moulton methods are efficient methods for propagating the time-dependent Kohn-Sham equations. Our integration schemes are implemented as an extension to the Quantum ESPRESSO code.

    View details for DOI 10.1063/1.5056258

    View details for PubMedID 30621412

  • New Assembly-Free Bulk Layered Inorganic Vertical Heterostructures with Infrared and Optical Bandgaps NANO LETTERS Antoniuk, E. R., Cheon, G., Krishnapriyan, A., Rehn, D. A., Zhou, Y., Reed, E. J. 2019; 19 (1): 142–49

    Abstract

    In principle, a nearly endless number of unique van der Waals heterostructures can be created through the vertical stacking of two-dimensional (2D) materials, resulting in unprecedented potential for material design. However, this widely employed synthetic method for generating van der Waals heterostructures is slow, imprecise, and prone to introducing interlayer contaminants when compared with synthesis methods that are scalable to industrially relevant scales. Herein, we study the properties of a new class of layered bulk inorganic materials that has recently been reported, which we call assembly-free bulk layered inorganic heterostructures, wherein the individual layers are of dissimilar chemical composition, distinguishing them from commonly studied layered materials. We find that these bulk materials exhibit properties similar to vertical heterostructures, but without the complex and unscalable stacking process. Using state-of-the-art computational approaches, we study the electronic properties of livingstonite (HgSb4S8), a naturally occurring mineral that is a bulk lattice-commensurate heterostructure. We find that isolated bilayers of livingstonite have an intralayer HSE-06 band gap of 2.08eV. This is the first report of a naturally occurring van der Waals heterostructure with a calculated band gap in the visible spectrum. We also studied the electronic properties of tetragonal Ti3Bi4O12, Sm2Ti3Bi2O12, orthorhombic Ti3Bi4O12, Nb3Bi5O15, LaTiNbBi2O9 and AgPbBrO and found some of them are potentially well suited for photovoltaic applications. We also provide characterization of the electronic structure of the isolated bilayer and monolayer subcomponents of the bulk heterostructures. The report of the properties of these materials significantly enhances the library of known van der Waals heterostructures.

    View details for DOI 10.1021/acs.nanolett.8b03500

    View details for Web of Science ID 000455561300017

    View details for PubMedID 30525679

  • Revealing the Spectrum of Unknown Layered Materials with Superhuman Predictive Abilities JOURNAL OF PHYSICAL CHEMISTRY LETTERS Cheon, G., Cubuk, E. D., Antoniuk, E. R., Blumberg, L., Goldberger, J. E., Reed, E. J. 2018; 9 (24): 6967–72

    Abstract

    We discover the chemical composition of over 1000 materials that are likely to exhibit layered and two-dimensional phases but have yet to be synthesized. This includes two materials our calculations indicate can exist in distinct structures with different band gaps, expanding the short list of two-dimensional phase change materials. While databases of over 1000 layered materials have been reported, we provide the first full database of materials that are likely layered but yet to be synthesized, providing a roadmap for the synthesis community. We accomplish this by combining physics with machine learning on experimentally obtained data and verify a subset of candidates using density functional theory. We find our model performs five times better than practitioners in the field at identifying layered materials and is comparable or better than professional solid-state chemists. Finally, we find that semi-supervised learning can offer benefits for materials design where labels for some of the materials are unknown.

    View details for DOI 10.1021/acs.jpclett.8b03187

    View details for Web of Science ID 000454752000007

    View details for PubMedID 30481462

  • Refrigeration in 2D: Electrostaticaloric effect in monolayer materials PHYSICAL REVIEW MATERIALS Rehn, D. A., Li, Y., Reed, E. J. 2018; 2 (11)
  • Microscopic Origins of the Variability of Water Contact Angle with Adsorbed Contaminants on Layered Materials JOURNAL OF PHYSICAL CHEMISTRY C Zhou, Y., Reed, E. J. 2018; 122 (32): 18520–27
  • The potential for fast van der Waals computations for layered materials using a Lifshitz model 2D MATERIALS Zhou, Y., Pellouchoud, L. A., Reed, E. J. 2017; 4 (2)
  • Data Mining for New Two- and One-Dimensional Weakly Bonded Solids and Lattice-Commensurate Heterostructures. Nano letters Cheon, G., Duerloo, K. N., Sendek, A. D., Porter, C., Chen, Y., Reed, E. J. 2017

    Abstract

    Layered materials held together by weak interactions including van der Waals forces, such as graphite, have attracted interest for both technological applications and fundamental physics in their layered form and as an isolated single-layer. Only a few dozen single-layer van der Waals solids have been subject to considerable research focus, although there are likely to be many more that could have superior properties. To identify a broad spectrum of layered materials, we present a novel data mining algorithm that determines the dimensionality of weakly bonded subcomponents based on the atomic positions of bulk, three-dimensional crystal structures. By applying this algorithm to the Materials Project database of over 50,000 inorganic crystals, we identify 1173 two-dimensional layered materials and 487 materials that consist of weakly bonded one-dimensional molecular chains. This is an order of magnitude increase in the number of identified materials with most materials not known as two- or one-dimensional materials. Moreover, we discover 98 weakly bonded heterostructures of two-dimensional and one-dimensional subcomponents that are found within bulk materials, opening new possibilities for much-studied assembly of van der Waals heterostructures. Chemical families of materials, band gaps, and point groups for the materials identified in this work are presented. Point group and piezoelectricity in layered materials are also evaluated in single-layer forms. Three hundred and twenty-five of these materials are expected to have piezoelectric monolayers with a variety of forms of the piezoelectric tensor. This work significantly extends the scope of potential low-dimensional weakly bonded solids to be investigated.

    View details for DOI 10.1021/acs.nanolett.6b05229

    View details for PubMedID 28191965

  • Holistic computational structure screening of more than 12 000 candidates for solid lithium-ion conductor materials ENERGY & ENVIRONMENTAL SCIENCE Sendek, A. D., Yang, Q., Cubuk, E. D., Duerloo, K. N., Cui, Y., Reed, E. J. 2017; 10 (1): 306-320

    View details for DOI 10.1039/c6ee02697d

    View details for Web of Science ID 000395208000028

  • Quantum Nuclear Effects in Stishovite Crystallization in Shock-Compressed Fused Silica JOURNAL OF PHYSICAL CHEMISTRY C Shen, Y., Reed, E. J. 2016; 120 (31): 17759-17766
  • Structural Phase Transitions by Design in Monolayer Alloys. ACS nano Duerloo, K. N., Reed, E. J. 2016; 10 (1): 289-297

    Abstract

    Two-dimensional monolayer materials are a highly anomalous class of materials under vigorous exploration. Mo- and W-dichalcogenides are especially unusual two-dimensional materials because they exhibit at least three different monolayer crystal structures with strongly differing electronic properties. This intriguing yet poorly understood feature, which is not present in graphene, may support monolayer phase engineering, phase change memory and other applications. However, knowledge of the relevant phase boundaries and how to engineer them is lacking. Here we show using alloy models and state-of-the-art density functional theory calculations that alloyed MoTe2-WTe2 monolayers support structural phase transitions, with phase transition temperatures tunable over a large range from 0 to 933 K. We map temperature-composition phase diagrams of alloys between pure MoTe2 and pure WTe2, and benchmark our methods to analogous experiments on bulk materials. Our results suggest applications for two-dimensional materials as phase change materials that may provide scale, flexibility, and energy consumption advantages.

    View details for DOI 10.1021/acsnano.5b04359

    View details for PubMedID 26647117

  • Structural semiconductor-to-semimetal phase transition in two-dimensional materials induced by electrostatic gating. Nature communications Li, Y., Duerloo, K. N., Wauson, K., Reed, E. J. 2016; 7: 10671-?

    Abstract

    Dynamic control of conductivity and optical properties via atomic structure changes is of technological importance in information storage. Energy consumption considerations provide a driving force towards employing thin materials in devices. Monolayer transition metal dichalcogenides are nearly atomically thin materials that can exist in multiple crystal structures, each with distinct electrical properties. By developing new density functional-based methods, we discover that electrostatic gating device configurations have the potential to drive structural semiconductor-to-semimetal phase transitions in some monolayer transition metal dichalcogenides. Here we show that the semiconductor-to-semimetal phase transition in monolayer MoTe2 can be driven by a gate voltage of several volts with appropriate choice of dielectric. We find that the transition gate voltage can be reduced arbitrarily by alloying, for example, for MoxW1-xTe2 monolayers. Our findings identify a new physical mechanism, not existing in bulk materials, to dynamically control structural phase transitions in two-dimensional materials, enabling potential applications in phase-change electronic devices.

    View details for DOI 10.1038/ncomms10671

    View details for PubMedID 26868916

  • Nanosecond homogeneous nucleation and crystal growth in shock-compressed SiO2 NATURE MATERIALS Shen, Y., Jester, S. B., Qi, T., Reed, E. J. 2016; 15 (1): 60-?

    View details for DOI 10.1038/NMAT4447

    View details for Web of Science ID 000366690600022

    View details for PubMedID 26461446

  • Piezoelectricity: Now in two dimensions. Nature nanotechnology Reed, E. J. 2015; 10 (2): 106-107

    View details for DOI 10.1038/nnano.2014.319

    View details for PubMedID 25531086

  • Strain engineering in monolayer materials using patterned adatom adsorption. Nano letters Li, Y., Duerloo, K. N., Reed, E. J. 2014; 14 (8): 4299-4305

    Abstract

    We utilize reactive empirical bond order (REBO)-based interatomic potentials to explore the potential for the engineering of strain in monolayer materials using lithographically or otherwise patterned adatom adsorption. In the context of graphene, we discover that the monolayer strain results from a competition between the in-plane elasticity and out-of-plane relaxation deformations. For hydrogen adatoms on graphene, the strain outside the adsorption region vanishes due to out-of-plane relaxation deformations. Under some circumstances, an annular adsorption pattern generates homogeneous tensile strains of approximately 2% in graphene inside the adsorption region, approximately 30% of the strain in the adsorbed region. We find that an elliptical adsorption pattern produces strains of as large as 5%, close to the strain in the adsorbed region. Also, nonzero maximum shear strain (∼4%) can be introduced by the elliptical adsorption pattern. We find that an elastic plane stress model provides qualitative guidance for strain magnitudes and conditions under which strain-diminishing buckling can be avoided. We identify geometric conditions under which this effect has potential to be scaled to larger areas. Our results elucidate a method for strain engineering at the nanoscale in monolayer devices.

    View details for DOI 10.1021/nl500974t

    View details for PubMedID 25051232

  • Structural phase transitions in two-dimensional Mo- and W-dichalcogenide monolayers. Nature communications Duerloo, K. N., Li, Y., Reed, E. J. 2014; 5: 4214-?

    Abstract

    Mo- and W-dichalcogenide compounds have a two-dimensional monolayer form that differs from graphene in an important respect: it can potentially have more than one crystal structure. Some of these monolayers exhibit tantalizing hints of a poorly understood structural metal-to-insulator transition with the possibility of long metastable lifetimes. If controllable, such a transition could bring an exciting new application space to monolayer materials beyond graphene. Here we discover that mechanical deformations provide a route to switching thermodynamic stability between a semiconducting and a metallic crystal structure in these monolayer materials. Based on state-of-the-art density functional and hybrid Hartree-Fock/density functional calculations including vibrational energy corrections, we discover that MoTe2 is an excellent candidate phase change material. We identify a range from 0.3 to 3% for the tensile strains required to transform MoTe2 under uniaxial conditions at room temperature. The potential for mechanical phase transitions is predicted for all six studied compounds.

    View details for DOI 10.1038/ncomms5214

    View details for PubMedID 24981779

  • Flexural Electromechanical Coupling: A Nanoscale Emergent Property of Boron Nitride Bilayers NANO LETTERS Duerloo, K. N., Reed, E. J. 2013; 13 (4): 1681-1686

    Abstract

    The symmetry properties of atomically thin boron nitride (BN) monolayers endow them with piezoelectric properties, whereas the bulk parent crystal of stacked BN layers is not piezoelectric. This suggests potential for unusual electromechanical properties in the few layer regime. In this work, we explore this regime and discover that a bilayer consisting of two BN monolayers exhibits a strong mechanical coupling between curvature and electric fields. Using a mechanical model with parameters obtained from density functional theory, we find that these bilayers amplify in-plane piezoelectric displacements by exceedingly large factors on the order of 10(3)-10(4). We find that this type of electromechanical coupling is an emergent nanoscale property that occurs only for the case of two stacked BN monolayers.

    View details for DOI 10.1021/nl4001635

    View details for Web of Science ID 000317549300051

    View details for PubMedID 23484488

  • Simulations of Shocked Methane Including Self-Consistent Semiclassical Quantum Nuclear Effects JOURNAL OF PHYSICAL CHEMISTRY A Qi, T., Reed, E. J. 2012; 116 (42): 10451-10459

    Abstract

    A methodology is described for atomistic simulations of shock-compressed materials that incorporates quantum nuclear effects on the fly. We introduce a modification of the multiscale shock technique (MSST) that couples to a quantum thermal bath described by a colored noise Langevin thermostat. The new approach, which we call QB-MSST, is of comparable computational cost to MSST and self-consistently incorporates quantum heat capacities and Bose-Einstein harmonic vibrational distributions. As a first test, we study shock-compressed methane using the ReaxFF potential. The Hugoniot curves predicted from the new approach are found comparable with existing experimental data. We find that the self-consistent nature of the method results in the onset of chemistry at 40% lower pressure on the shock Hugoniot than observed with classical molecular dynamics. The temperature shift associated with quantum heat capacity is determined to be the primary factor in this shift.

    View details for DOI 10.1021/jp308068c

    View details for Web of Science ID 000310120800022

    View details for PubMedID 23013329

  • Intrinsic Piezoelectricity in Two-Dimensional Materials JOURNAL OF PHYSICAL CHEMISTRY LETTERS Duerloo, K. N., Ong, M. T., Reed, E. J. 2012; 3 (19): 2871-2876

    View details for DOI 10.1021/jz3012436

    View details for Web of Science ID 000309505400023

  • Ultrafast Detonation of Hydrazoic Acid (HN3) PHYSICAL REVIEW LETTERS Reed, E. J., Rodriguez, A. W., Manaa, M. R., Fried, L. E., Tarver, C. M. 2012; 109 (3)

    Abstract

    The fastest self-sustained chemical reactions in nature occur during detonation of energetic materials where reactions are thought to occur on nanosecond or longer time scales in carbon-containing materials. Here we perform the first atomistic simulation of an azide energetic material, HN3, from the beginning to the end of the chemical evolution and find that the time scale for complete decomposition is a mere 10 ps, orders of magnitude shorter than that of secondary explosives and approaching the fundamental limiting time scale for chemistry; i.e., vibrational time scale. We study several consequences of the short time scale including a state of vibrational disequilibrium induced by the fast transformations.

    View details for DOI 10.1103/PhysRevLett.109.038301

    View details for Web of Science ID 000306466900025

    View details for PubMedID 22861903

  • Engineered Piezoelectricity in Graphene ACS NANO Ong, M. T., Reed, E. J. 2012; 6 (2): 1387-1394

    Abstract

    We discover that piezoelectric effects can be engineered into nonpiezoelectric graphene through the selective surface adsorption of atoms. Our calculations show that doping a single sheet of graphene with atoms on one side results in the generation of piezoelectricity by breaking inversion symmetry. Despite their 2D nature, piezoelectric magnitudes are found to be comparable to those in 3D piezoelectric materials. Our results elucidate a designer piezoelectric phenomenon, unique to the nanoscale, that has potential to bring dynamical control to nanoscale electromechanical devices.

    View details for DOI 10.1021/nn204198g

    View details for Web of Science ID 000300757900046

    View details for PubMedID 22196055

  • Electron-Ion Coupling in Shocked Energetic Materials JOURNAL OF PHYSICAL CHEMISTRY C Reed, E. J. 2012; 116 (3): 2205-2211

    View details for DOI 10.1021/jp206769c

    View details for Web of Science ID 000299584400022

  • Observation of terahertz radiation coherently generated by acoustic waves.  Nature Physics  Reed, E., J., Armstrong, M., R. et al. 2009; 5: 285-288

    View details for DOI 10.1038/nphys1219

  • Theoretical potential for low energy consumption phase change memory utilizing electrostatically-induced structural phase transitions in 2D materials NPJ COMPUTATIONAL MATERIALS Rehn, D. A., Li, Y., Pop, E., Reed, E. J. 2018; 4
  • COMPUTATIONAL MATERIALS SCIENCE Two-dimensional tellurium NATURE Reed, E. J. 2017; 552 (7683): 1–2
  • Structural phase transition in monolayer MoTe2 driven by electrostatic doping NATURE Wang, Y., Xiao, J., Zhu, H., Li, Y., Alsaid, Y., Fong, K., Zhou, Y., Wang, S., Shi, W., Wang, Y., Zettl, A., Reed, E. J., Zhang, X. 2017; 550 (7677): 487-+

    Abstract

    Monolayers of transition-metal dichalcogenides (TMDs) exhibit numerous crystal phases with distinct structures, symmetries and physical properties. Exploring the physics of transitions between these different structural phases in two dimensions may provide a means of switching material properties, with implications for potential applications. Structural phase transitions in TMDs have so far been induced by thermal or chemical means; purely electrostatic control over crystal phases through electrostatic doping was recently proposed as a theoretical possibility, but has not yet been realized. Here we report the experimental demonstration of an electrostatic-doping-driven phase transition between the hexagonal and monoclinic phases of monolayer molybdenum ditelluride (MoTe2). We find that the phase transition shows a hysteretic loop in Raman spectra, and can be reversed by increasing or decreasing the gate voltage. We also combine second-harmonic generation spectroscopy with polarization-resolved Raman spectroscopy to show that the induced monoclinic phase preserves the crystal orientation of the original hexagonal phase. Moreover, this structural phase transition occurs simultaneously across the whole sample. This electrostatic-doping control of structural phase transition opens up new possibilities for developing phase-change devices based on atomically thin membranes.

    View details for DOI 10.1038/nature24043

    View details for Web of Science ID 000413697800036

    View details for PubMedID 29019982

  • Statistical learning of kinetic Monte Carlo models of high temperature chemistry from molecular dynamics Yang, Q., Sing-Long, C., Chen, E., Reed, E. AMER CHEMICAL SOC. 2017
  • Hundreds of new two- and one-dimensional weakly bonded solids and lattice-commensurate heterostructures via data mining Reed, E., Sendek, A., Duerloo, K., Porter, C., Chen, Y., Reed, E. AMER CHEMICAL SOC. 2017
  • Films. ACS nano Empante, T. A., Zhou, Y., Klee, V., Nguyen, A. E., Lu, I., Valentin, M. D., Naghibi Alvillar, S. A., Preciado, E., Berges, A. J., Merida, C. S., Gomez, M., Bobek, S., Isarraraz, M., Reed, E. J., Bartels, L. 2017; 11 (1): 900-905

    Abstract

    Chemical vapor deposition allows the preparation of few-layer films of MoTe2 in three distinct structural phases depending on the growth quench temperature: 2H, 1T', and 1T. We present experimental and computed Raman spectra for each of the phases and utilize transport measurements to explore the properties of the 1T MoTe2 phase. Density functional theory modeling predicts a (semi-)metallic character. Our experimental 1T films affirm the former, show facile μA-scale source-drain currents, and increase in conductivity with temperature, different from the 1T' phase. Variation of the growth method allows the formation of hybrid films of mixed phases that exhibit susceptibility to gating and significantly increased conductivity.

    View details for DOI 10.1021/acsnano.6b07499

    View details for PubMedID 27992719