2024 New's Items

AlabOS: a Python-based reconfigurable workflow management framework for autonomous laboratories

Fei Y
Rendy B
Kumar R
Dartsi O
Sahasrabuddhe HP
McDermott MJ
2024

The recent advent of autonomous laboratories, coupled with algorithms for high-throughput screening and active learning, promises to accelerate materials discovery and innovation. As these autonomous systems grow in complexity, the demand for robust and efficient workflow management software becomes increasingly critical. In this paper, we introduce AlabOS, a general-purpose software framework for orchestrating experiments and managing resources, with an emphasis on automated laboratories for materials synthesis and characterization. AlabOS features a reconfigurable experiment workflow...

Phonon screening and dissociation of excitons at finite temperatures from first principles

Alvertis M
Haber JB
Li Z
Coveney CJN
Louie SG
Filip MR
Neaton JB
2024

The properties of excitons, or correlated electron–hole pairs, are of paramount importance to optoelectronic applications of materials. A central component of exciton physics is the electron–hole interaction, which is commonly treated as screened solely by electrons within a material. However, nuclear motion can screen this Coulomb interaction as well, with several recent studies developing model approaches for approximating the phonon screening of excitonic properties. While these model approaches tend to improve agreement with experiment, they rely on several approximations that...

Entropic Effects on Diamine Dynamics and CO2 Capture in Diamine-Appended Mg2(dopbdc) Metal–Organic Frameworks

Shaidu Y
DeSnoo W
Smith A
Taw E
Perkins CL
Neaton JB
Neaton JB
2024

Recent measurements [Xu, J.; J. Phys. Chem. Lett.2019, 10 (22), 7044−7049] have reported temperature-dependent rates of detachment of diamine from Mg sites in diamine-appended Mg2(dobpdc) [dobpdc4– = 4,4′-dihydroxy(1,1′-biphenyl)-3,3′-dicarboxylic] metal–organic frameworks, a process hypothesized to be a precursor for cooperative CO2 adsorption, leading to step-shaped isotherms or isobars. Here, we compute the rate of diamine exchange...

High-Coherence Kerr-Cat Qubit in 2D Architecture

2024

The Kerr-cat qubit is a bosonic qubit in which multiphoton Schrödinger cat states are stabilized by applying a two-photon drive to an oscillator with a Kerr nonlinearity. The suppressed bit-flip rate with increasing cat size makes this qubit a promising candidate to implement quantum error correction codes tailored for noise-biased qubits. However, achieving strong light-matter interactions necessary for stabilizing and controlling this qubit has traditionally required strong microwave drives that heat the qubit and degrade its performance. In contrast, increasing the coupling to the...

Machine Learned Potential for High-Throughput Phonon Calculations of Metal-Organic Frameworks

Elena, A. M.
Kamath, P. D.
Inizan, T. J.
Rosen, A. S.
Zanca, F.
Persson, K. A.
2024

Metal–organic frameworks (MOFs) are highly porous and versatile materials studied extensively for applications such as carbon capture and water harvesting. However, computing phonon-mediated properties in MOFs, like thermal expansion and mechanical stability, remains challenging due to the large number of atoms per unit cell, making traditional Density Functional Theory (DFT) methods impractical for high-throughput screening. Recent advances in machine learning potentials have led to foundation atomistic models, such as MACE-MP-0, that accurately predict equilibrium structures but struggle...

Alkali-Ion-Assisted Activation of ε-VOPO4 as a Cathode Material for Mg-Ion Batteries

Sari, D.
Rutt, A.
Kim, J.
Chen, Q.
Hahn, N. T.
Kim, H.
Persson, K. A.
Ceder, G.
2024

Rechargeable multivalent-ion batteries are attractive alternatives to Li-ion batteries to mitigate their issues with metal resources and metal anodes. However, many challenges remain before they can be practically used due to the low solid-state mobility of multivalent ions. In this study, a promising material identified by high-throughput computational screening is investigated, ε-VOPO4, as a Mg cathode. The experimental and computational evaluation of ε-VOPO4 suggests that it may provide an energy density of >200 Wh kg−1 based on the average...

Unraveling the mechanisms of triplet state formation in a heavy-atom free photosensitizer

Fay, T. P.
Limmer, D. T.
2024

Triplet excited state generation plays a pivotal role in photosensitizers, however the reliance on transition metals and heavy atoms can limit the utility of these systems. In this study, we demonstrate that an interplay of competing quantum effects controls the high triplet quantum yield in a prototypical boron dipyrromethene-anthracene (BD-An) donor–acceptor dyad photosensitizer, which is only captured by an accurate treatment of both inner and outer sphere reorganization energies. Our ab initio-derived model provides excellent agreement with experimentally measured spectra,...

Splitting probabilities as optimal controllers of rare reactive events

Singh, A. N.
Limmer, D. T
2024

The committor constitutes the primary quantity of interest within chemical kinetics as it is understood to encode the ideal reaction coordinate for a rare reactive event. We show the generative utility of the committor in that it can be used explicitly to produce a reactive trajectory ensemble that exhibits numerically exact statistics as that of the original transition path ensemble. This is done by relating a time-dependent analog of the committor that solves a generalized bridge problem to the splitting probability that solves a boundary value problem under a bistable assumption. By...

Design principles for energy transfer in the photosystem II supercomplex from kinetic transition networks

Yang, S. J.
Wales, D. J.
Woods, E. J.
Fleming, G. R.
2024

Photosystem II (PSII) has the unique ability to perform water-splitting. With light-harvesting complexes, it forms the PSII supercomplex (PSII-SC) which is a functional unit that can perform efficient energy conversion, as well as photoprotection, allowing photosynthetic organisms to adapt to the naturally fluctuating sunlight intensity. Achieving these functions requires a collaborative energy transfer network between all subunits of the PSII-SC. In this work, we perform kinetic analyses and characterise the energy landscape of the PSII-SC with a structure-based energy transfer model....

SiGe/Si heterojunction drain transistor for faster 3D NAND flash memory erase

Dasom Lee
Tsu-Jae King Liu
2024
Some 3D NAND flash memory technologies utilize the phenomenon of Gate Induced Drain Leakage (GIDL) for erase operation. As the number of memory cells stacked in a 3D NAND string increases, larger GIDL current is needed to maintain the same erase speed. In this work, the use of silicon-germanium (SiGe), which has a smaller band-gap energy compared to silicon (Si), is proposed to augment GIDL current through enhanced band-to-band tunneling. TCAD simulation confirms that, when the heavily doped drain and a portion of the undoped channel region of the drain transistor comprise SiGe, both GIDL...