2022 New's Items

High-fidelity three-qubit iToffoli gate for fixed-frequency superconducting qubits

Kim Y
Morvan A
Nguyen LB
Mark J
Naik RK
Jünger C
Chen L
Kreikebaum JM
Santiago DI
Siddiqi I
2022

The development of noisy intermediate-scale quantum devices has extended the scope of executable quantum circuits with high-fidelity single- and two-qubit gates. Equipping these devices with three-qubit gates will enable the realization of more complex quantum algorithms and efficient quantum error correction protocols with reduced circuit depth. Several three-qubit gates have been implemented for superconducting qubits, but their use in gate synthesis has been limited owing to their low fidelity. Here, using fixed-frequency superconducting qubits, we demonstrate a high-fidelity...

Gas-phase synthesis of racemic helicenes and their potential role in the enantiomeric enrichment of sugars and amino acids in meteorites

Kaiser, R. I.
Zhao, L.
Ahmed, M.
Evseev M. M.
Azyazov, V. N.
Mebel, A. M.
Mohamed, R. K.
Fischer, F. R.
Li, X.
2022

The molecular origins of homochirality on Earth is not understood well, particularly how enantiomerically enriched molecules of astrobiological significance like sugars and amino acids might have been synthesized on icy grains in space preceding their delivery to Earth. Polycyclic aromatic hydrocarbons (PAHs) identified in carbonaceous chondrites could have been processed in molecular clouds by circularly polarized light prior to the depletion of enantiomerically enriched helicenes onto carbonaceous grains resulting in chiral islands. However, the fundamental low temperature reaction...

Magnetic Interactions in Substitutional Core-Doped Graphene Nanoribbons

Wen, E. C. H.
Jacobse, P. H.
Jiang, J.
Wang, Z.
McCurdy, R. D.
Louie, S. G.
Crommie, M. F.
Fischer, F. R. J. Am.
2022

The design of a spin imbalance within the crystallographic unit cell of bottom-up engineered 1D graphene nanoribbons (GNRs) gives rise to nonzero magnetic moments within each cell. Here, we demonstrate the bottom-up assembly and spectroscopic characterization of a one-dimensional Kondo spin chain formed by a chevron-type GNR (cGNR) physisorbed on Au(111). Substitutional nitrogen core doping introduces a pair of low-lying occupied states per monomer within the semiconducting gap of cGNRs. Charging resulting from the interaction with the gold substrate quenches one electronic state for...

Charge transport in topological graphene nanoribbons and nanoribbon heterostructures

Mangnus, M. J. J.
Fischer, F. R.
Crommie, M. F.
Swart, I.
Jacobse, P. H.
2022

Although it is generally accepted that structural parameters like width, shape, and edge structure crucially affect the electronic characteristics of graphene nanoribbons (GNRs), the exact relationship between geometry and charge transport remains largely unexplored. In this paper, we present in situ through-transport measurements of various topological GNRs and GNR heterostructures by lifting the ribbon with the tip of a scanning tunneling microscope. At the same time, we develop a comprehensive transport model that enables us to understand various features, such as...

Innovating at Speed and at Scale: A Next Generation Infrastructure for Accelerating Semiconductor Technologies

Gottscho RA
Levine EV
Liu TJ
McIntyre PC
Mitra S
Murmann B
Rabaey JM
Salahuddin S
Shih WC
Wong HS
2022

Semiconductor innovation drives improvements to technologies that are critical to modern society. The country that successfully accelerates semiconductor innovation is positioned to lead future semiconductor-driven industries and benefit from the resulting economic growth. It is our view that a next generation infrastructure is necessary to accelerate and enhance semiconductor innovation in the U.S. In this paper, we propose such an advanced infrastructure composed of a national network of facilities with enhancements in technology and business models. These enhancements enable...

Simulation-Based Study of Low Minimum Operating Voltage SRAM With Inserted-Oxide FinFETs and Gate-All-Around Transistors

Wu YT
Ding F
Chiang MH
Chen JF
Liu TJK
2022

A six-transistor (6T) static random access memory (SRAM) cell design comprising inserted-oxide fin field-effect transistors (iFinFETs) is compared against other 6T SRAM cell designs comprising either FinFETs, gate-all-around (GAA) nanowire field-effect transistors (NWFETs), or forksheet field-effect transistors (FSHFETs). The FSHFET and iFinFET SRAM exhibit better read stability, write ability, and lower minimum operating voltage ( Vmin...

Non-Volatile Nano-Electro-Mechanical Switches and Hybrid Circuits in a 16 nm CMOS Back-End-of-Line Process

Sikder U
Naous R
Stojanović V
Liu TJK
2022

Reprogrammable non-volatile (NV) vertically-oriented nano-electro-mechanical (NEM) switches with a compact footprint are successfully implemented using multiple back-end-of-line (BEOL) interconnect layers of a standard 16-nm CMOS process technology, with no additional lithography steps. A compact decoder circuit comprising an array of these reconfigurable interconnects is successfully demonstrated. As the minimum metal pitch decreases with each new manufacturing process generation, hybrid CMOS+NEM technology becomes increasingly attractive for ultra-low-power reconfigurable computing...

Chloride-Assisted Corrosion of Copper and Protection by Benzotriazole

Yang S
Zhao X
Qi Z
Lu Y-H
Somorjai G
Yang P
Baskin A
Prendergast D
Salmeron M
2022

The structure and composition of copper surfaces in aqueous solutions of benzotriazole (BTAH) and NaCl was investigated by sum frequency vibrational spectroscopy as a function of concentration and bias during cyclic voltammetry experiments. We found that the protection provided by the BTAH films formed at the copper surface is effective for negative bias voltages below the open circuit potential (OCP) but not at positive voltages where Cl– displaces BTAH. By measuring the Gibbs adsorption energy of BTAH and Cl–, we found that a...

Ferroelectricity in a semiconducting all-inorganic halide perovskite

Zhang Y
Parsonnet E
Fernandez A
Behera P
Pan X
Ramesh R
Yang P
2022

Ferroelectric semiconductors are rare materials with both spontaneous polarizations and visible light absorptions that are promising for designing functional photoferroelectrics, such as optical switches and ferroelectric photovoltaics. The emerging halide perovskites with remarkable semiconducting properties also have the potential of being ferroelectric, yet the evidence of robust ferroelectricity in the typical three-dimensional hybrid halide perovskites has been elusive. Here, we report on the investigation of ferroelectricity in all-inorganic halide perovskites, CsGeX...

The Interactive Dynamics of Nanocatalyst Structure and Microenvironment during Electrochemical CO2 Conversion

Yu S
Louisia S
Yang P
2022

In the pursuit of a decarbonized society, electrocatalytic CO2 conversion has drawn tremendous research interest in recent years as a promising route to recycling CO2 into more valuable chemicals. To achieve high catalytic activity and selectivity, nanocatalysts of diverse structures and compositions have been designed. However, the dynamic structural transformation of the nanocatalysts taking place under operating conditions makes it difficult to study active site configurations present during the CO2...