Hrvoje Petek Writes a News and Views Article in Nature Nanotechnology

  • By Aude Marjolin
  • 10 January 2017

Photovoltaics in action: Electron motion in a type-II InSe/GaAs semiconductor heterostructure has been recorded in a movie immediately after photoexcitation with high spatial and temporal resolution.

Electrons are the lifeblood of semiconductor devices, from transistors that power computers and smart phones, and semiconductor diodes that light up the night, to photovoltaic cells that harvest solar energy to power it all. Under the influence of applied voltages or light stimulations, electrons flow through nanoscale channels and plummet potential gradients at interfaces of disparate materials. In a semiconductor device this ebb and flow occurs several times every nanosecond within billions of transistors on a single microchip, unseen by human eye, but creating text, images and movies in strings of 0s and 1s. But the true time and spatial scales on which electrons are energized and transported span a range of hundreds of femtoseconds and tens of nanometres. Thus, to capture in a movie the physical phenomena of electrons in a device requires a truly extraordinary camera. Writing in Nature Nanotechnology, Man et al. report an experiment that performs just that. Specifically, they record a movie of electron flow in energy, space and time within a semiconductor heterojunction composed of GaAs in physical contact with InSe by imaging electrons emitted into vacuum through the joint action of femtosecond duration IR generation and UV electron emission laser pulses.

David Snoke's PRL Article Highlighted in Physics Viewpoint

  • By Aude Marjolin
  • 9 January 2017

Matter-Light Condensates Reach Thermal Equilibrium

Making use of improved microcavities, hybrid condensates of matter and light can be tuned to reach a thermal equilibrium state, despite their finite lifetime.

In a laser, coherent light is created by stimulated emission of photons from an “inverted” state of matter that is significantly out of thermal equilibrium. “Inverted” means that excited states of the matter are more occupied than lower energy states, so that emission is more likely than absorption. The coherence of laser light is closely related to a quite different, and less commonly encountered, state of matter—a Bose-Einstein condensate (BEC). In the textbook description of a BEC, at low enough temperatures or high enough densities, a large number of particles occupy the same state, producing a coherent state of matter. In contrast to laser light, the textbook BEC is in thermal equilibrium. Condensates of polaritons—half-light, half-matter quasiparticles—have so far been found in conditions halfway between those of an equilibrium BEC and those of a laser. Work by David Snoke and colleagues now shows that such polariton condensates can be tuned to reach a thermal equilibrium state. With this tunability between an equilibrium and nonequilibrium state, researchers can explore how the character of phase transitions evolves between the two limits.

Peng Liu receives CAREER Award

  • By Aude Marjolin
  • 16 December 2016

Peng Liu has been selected to receive a National Science Foundation CAREER award based upon his proposal, entitled "Computational Studies of Transition-Metal-Catalyzed Reactions in Organic Synthesis." 

In this CAREER project funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Peng Liu of the Department of Chemistry at the University of Pittsburgh is developing new strategies to use computational tools to investigate mechanisms and effects of ancillary ligands in transition-metal-catalyzed reactions of unactivated starting materials, such as C-C and C-H bonds, and unactivated olefins. The goal of this research is to reveal the fundamental reactivity rules of common organometallic intermediates in these transformations and to develop new models to interpret ligand effects on reactivity and selectivity. This proposal’s educational and outreach plan aims to maximize the power of computations to enhance learning of organic chemistry concepts and to facilitate synthetic organic chemistry research. Professor Liu’s team will develop virtual reality (VR) software and educational materials to visualize three-dimensional molecular structures and reaction mechanism videos in an interactive and immersive environment.

Postdoctoral Fellowship: Eberly Research Fellows at Penn State University

  • By Aude Marjolin
  • 12 December 2016

The Eberly College of Science at Penn State University invites nominees for the Eberly Research Fellowship program. Eberly Fellowships are designed to attract exceptional early career scientists to Penn State to enhance their career goals in the vibrant, highly collaborative environment of the Eberly College of Science and the broader STEM community of Penn State University.

New Catalyst That Advances Capture and Conversion of Atmospheric Carbon Dioxide

  • By Aude Marjolin
  • 7 December 2016

Karl Johnson CST cover imageResearch focused on developing a new catalyst that would lead to large-scale implementation of capture and conversion of carbon dioxide (CO2) was recently published in the Royal Society of Chemistry journal Catalysis Science & Technology. Principal investigator is Karl Johnson, and postdoctoral associate Jingyun Ye is lead author. The article “Catalytic Hydrogenation of CO2 to Methanol in a Lewis Pair Functionalized MOF” is featured on the cover of Catalysis Science & Technology vol. 6, no. 24 and builds upon Johnson’s previous research that identified the two main factors for determining the optimal catalyst for turning atmospheric CO2 into liquid fuel. The research was conducted using computational resources at the University’s Center for Simulation and Modeling. 

Sara Majetich Named IEEE Fellow

  • By Aude Marjolin
  • 5 December 2016

Sara Majetich has been named an IEEE Fellow. Majetich is being recognized for her contributions to the understanding of magnetic nanoparticles. She studies the fundamental physics of magnetic nanoparticles that have very uniform sizes and applies her work to the design of functional materials that have applications in data storage media, high-speed electronics and biomedicine.

Fellowship is the highest grade of membership in IEEE, and is considered to be a prestigious honor among the technical community. Fellowship is conferred by the IEEE Board of Directors on only one-tenth of one percent of the total voting membership of the organization each year. The distinction recognizes outstanding accomplishments in any of the IEEE’s fields of interest, which focus on advancing technology for the benefit of humanity.

The IEEE is the world’s leading professional association for advancing technology for humanity. Through its more than 400,000  members in 160 countries, the association is a leading authority on a wide variety of areas ranging from aerospace systems, computers and telecommunications to biomedical engineering, electric power and consumer electronics.

Science2016 Poster Award Winners

  • By Aude Marjolin
  • 5 December 2016

Congratulations to the Science2016 Poster Award Winners!

Dr. Ran Cheng (Xiao's group, CMU Physics), Ms. Xing Yee Gan (Millstone Group, Pitt Chemistry), Mr. Clinton Johnson (Garrett-Roe Lab, Pitt Chemistry), Ms. Megan Kirkendall (Levy Lab, Pitt Physics), Mr. Jun Li (Feenstra Group, CMU Physics), and Mr. Jierui Liang (Fullerton group, Pitt, Chemical Engineering) won a $1,000 award for conference travel in 2017 and an Amazon Echo Dot.

Snapshots of Proton Conduction Process in Water

  • By Aude Marjolin
  • 5 December 2016

Scientists Capture Snapshots of the Proton Conduction Process in Water

The motion of protons (positively charged H atoms) in water is associated with water’s conduction of electricity and is involved in many important processes including vision, signaling in biological systems, photosynthesis and, the operation of fuel cells. Both artificial photosynthetic systems and fuel cells are of growing interest for clean energy technologies. However, the details of how protons move in water have remained elusive, and an enhanced understanding of the nature of this process is needed to improve the technologies that depend on proton transfer.

An international team of scientists, including a University of Pittsburgh professor and graduate student, has used spectroscopic methods to obtain snapshots of the process by which a proton is relayed from one water molecule to the next. The research is published in a paper in the December 2, 2016 issue of the journal Science.

Hrvoje Petek and David Waldeck named AAAS Fellows

  • By Aude Marjolin
  • 22 November 2016

Hrvoje Petek and David Waldeck were recently elected AAAS Fellows in Physics and Chemistry, respectively.

In October 2016, the AAAS Council elected 391 members as Fellows of the association, in recognition of their contributions to innovation, education, and scientific leadership. The tradition of electing AAAS Fellows began in 1874 to recognize members for their scientifically or socially distinguished efforts to advance science or its applications. 

The 2016 AAAS fellows will be recognized at AAAS' 2017 annual meeting where they will be presented a rosette pin, its gold and blue colors signify science and engineering, respectively. 

View all the elected fellows here.

Fundamentals of Quantum Materials Winter School (January 16-19, 2017)

  • By Aude Marjolin
  • 9 November 2016

The inaugural Fundamentals of Quantum Materials Winter School will be held at the University of Maryland, January 16-19, 2017 at the University of Maryland, College Park, MD.

This school, sponsored by ICAM and the Gordon & Betty Moore Foundation, is aimed at providing fundamental training to our current and future generations of Quantum Materials scientists in synthesis and characterization techniques. It will bring together senior and junior scientists to address topics at the forefront of current research into quantum materials, while also providing pedagogical background and practical training for junior scientists. With an interdisciplinary and diverse crowd including physicists, chemists, and materials scientists, participants will gain a basic functional knowledge of how to plan and carry out synthesis relevant to the study of quantum materials, and will have a unique opportunity to interact with some of the top researchers in the field while networking with fellow peers.