2021 New's Items

Paul Alivisatos Named President of University of Chicago

February 26, 2021

Chemist Paul Alivisatos, who directed the Lawrence Berkeley National Laboratory for seven years and served the UC Berkeley campus as vice chancellor for research and currently as executive vice chancellor and provost — all while continuing his pioneering work in nanocrystals — has been appointed president of the University of Chicago, his alma mater.

Alivisatos, the Samsung Distinguished Professor of Nanoscience and Nanotechnology, will remain in his current position at Berkeley through the end of the spring semester.

“I can think of no one better suited for this...

The Frontiers of Knowledge Award goes to Paul Alivisatos

February 24, 2021

Scientists have long been fascinated by the way in which light interacts with matter, and the quest to control this interaction in fine detail is at the basis of some of today’s most powerful technologies. Alivisatos and Grätzel are leaders in controlling the play of light-matter through the use of nanomaterials that act upon the latter. The committee recognizes them as key figures in the fundamental science that led to “the development of nanostructured materials for energy-related applications.”

Grätzel – nominated by Jean S. Hesthaven, dean of the School of Basic Sciences at the...

David Limmer Awarded 2021 Alfred P. Sloan Fellowship

February 16, 2021

The College of Chemistry is pleased to announce that David Limmer, Assistant Chemistry Professor and Chevron Chair in Chemistry, has been awarded a 2021 Fellowship by the Alfred P. Sloan Foundation(link is external). He joins the ranks of 126 early-career scholars in several scientific disciplines from Canada and the United States who have been selected for this year.

Matthew...

Crystalline symmetry-protected non-trivial topology in prototype compound BaAl4

Wang K.
Mori R.
Wang Z.
Wang L.
Han Son Ma J.
Latzke DW
Graf DE
Denlinger JD
Campbell D.
Bernevig BA
Lanzara A.
Paglione J.
2021

The BaAl4 prototype crystal structure is the most populous of all structure types, and is the building block for a diverse set of sub-structures including the famous ThCr2Si2 family that hosts high-temperature superconductivity and numerous magnetic and strongly correlated electron systems. The MA4 family of materials (M = Sr, Ba, Eu; A = Al, Ga, In) themselves present an intriguing set of ground states including charge and spin orders, but have largely been considered as...

Present and future trends in spin ARPES

Lin C-Y
Moreschini L
Lanzara A
2021

Spin-orbit (SO) coupling combined with space inversion symmetry breaking is at the origin of the lifting of the spin degeneracy in the band structure of many materials. The momentum-dependent energy splitting and the degree of spin polarization are indicative of the strength and symmetry of the SO interaction, and enter in the figure of merit of essentially all conceptual designs aiming to control the electron spin degree of freedom in solids. Here we briefly review the role played by spin-and-angle–resolved photoemission (spin ARPES or SARPES) in revealing the spin polarization...

Spin–orbit torque rectifier for weak RF energy harvesting

Sayeda S
Salahuddin S
Yablonovitch E
2021
We propose a rectifier concept, simultaneously utilizing the Hall effect and the spin–orbit-torque, that is well matched to the low impedance of antennas. This rectifier is promising for general radio detection and, particularly, for harvesting ambient weak radio signals, where conventional rectification fails to operate. The Hall effect and spin–orbit-torque are both proportional to current density, which improves inversely with the device cross-sectional area, providing a large signal at the nanoscale. A single device made using existing materials can provide 200 μV DC from 500 nW of radio...

Efficient spontaneous emission by metal-dielectric antennas; antenna Purcell factor explained

Hooten S
Andrade NM
Wu MC
Yablonovitch E
2021

The rate of spontaneous emission from an optical emitter can be greatly enhanced using a metallic optical antenna at the penalty of efficiency. In this paper we propose a metal-dielectric antenna that eliminates the tradeoff between spontaneous emission enhancement and radiative efficiency by using nanoscopic dielectric structures at the antenna tips. This tradeoff occurs due to Ohmic loss and is further exacerbated by electron surface collisions. We find that our metal-dielectric antenna can enhance spontaneous emission by a factor 5 × 105 with efficiency...

Mechanism of Methanol Decomposition over Single-Site Pt1/CeO2 Catalyst: A DRIFTS Study

Qi Z
Chen L
Zhang S
Su J
Somorjai GA
2021

Single-site catalysts have drawn broad attention in catalysis because of their maximum atomic utilization and unique catalytic performance. Early work in our group has shown a 40-fold higher activity of methanol decomposition over single-site Pt1/CeO2 catalyst than CeO2 supported 2.5 nm Pt nanoparticles, while a molecular-level understanding of such enhancement is lacking. Herein, the reaction mechanism of methanol decomposition over Pt1/CeO2 was carefully...

Stabilized open metal sites in bimetallic metal–organic framework catalysts for hydrogen production from alcohols

Snider JL
Su J
Verma P
Gabaly FE
Sugar JD
Chen L
Chames JM
Talin AA
Dun C
Urban JJ
Stavila V
Prendergast D
Somorjaibd GA
Allendorf MD
2021

Liquid organic hydrogen carriers such as alcohols and polyols are a high-capacity means of transporting and reversibly storing hydrogen that demands effective catalysts to drive the (de)hydrogenation reactions under mild conditions. We employed a combined theory/experiment approach to develop MOF-74 catalysts for alcohol dehydrogenation and examine the performance of the open metal sites (OMS), which have properties analogous to the active sites in high-performance single-site catalysts and homogeneous catalysts. Methanol dehydrogenation was used as a model reaction system for...

Metallic Nanoparticles in Heterogeneous Catalysis

Sápi A
Rajkumar T
Kiss J
Kukovecz A
Konya Z
Somorjai GA
2021

Heterogeneous catalysis is a chemical process achieved at solid–gas or solid–liquid interfaces. Many factors including the particle size, shape and metal-support interfaces can have significant influences on the catalytic properties of metal catalysts. The recent progress in the synthesis techniques and advanced characterization tools allow to understand the catalytic mechanisms at molecular level. In this Review, the size and shape dependent catalytic chemistry of metal nanoparticles and their electronic properties will be discussed. Then the unique catalytic chemistry at the metal-...