Tootfinder

Controlled Spalling of Single Crystal 4H-SiC Bulk Substrates
Connor P Horn, Christina Wicker, Antoni Wellisz, Cyrus Zeledon, Pavani Vamsi Krishna Nittala, F Joseph Heremans, David D Awschalom, Supratik Guha
https://arxiv.org/abs/2404.19716 https://arxiv.org/pdf/2404.19716
arXiv:2404.19716v1 Announce Type: new
Abstract: We detail several scientific and engineering innovations which enable the controlled spalling of 10 - 50 micron thick films of single crystal 4H silicon carbide (4H-SiC) from bulk substrates. 4H-SiC's properties, including high thermal conductivity and a wide bandgap, make it an ideal candidate for high-temperature, high-voltage power electronic devices. Moreover, 4H-SiC has been shown to be an excellent host of solid-state atomic defect qubits for quantum computing and quantum networking. Because 4H-SiC single crystal substrates are expensive (due to long growth times and limited yield), techniques for removal and transfer of layers in the tens-of-microns thickness range are highly desirable for substrate reuse and heterogenous integration of separated layers. In this work we utilize novel approaches for stressor layer thickness control and spalling crack initiation to demonstrate controlled spalling of 4H-SiC, the highest fracture toughness material spalled to date. Additionally, we demonstrate substrate re-use, bonding of the spalled films to carrier substrates, and explore the spin coherence of the spalled films. In preliminary studies we are able to achieve coherent spin control of neutral divacancy ($VV^{0}$) qubit ensembles and measure a spin T2* of 0.581 $\mu$s in such spalled films.

First observation of $\Lambda_{b}^{0} \rightarrow \Sigma_c^{(*) } D^{(*)-} K^{-}$ decays
LHCb collaboration, et al.
https://arxiv.org/abs/2404.19510 https://arxiv.org/pdf/2404.19510
arXiv:2404.19510v1 Announce Type: new
Abstract: The four decays, $\Lambda_{b}^{0} \rightarrow \Sigma_c^{(*) } D^{(*)-} K^{-}$, are observed for the first time using proton-proton collision data collected with the LHCb detector at a centre-of-mass energy of $13\,\rm{TeV}$, corresponding to an integrated luminosity of $6\,\rm{fb}^{-1}$. By considering the $\Lambda_b^0 \rightarrow \Lambda_c^{ } \overline{D}^0 K^{-}$ decay as reference channel, the following branching fraction ratios are measured to be,
$$\frac{\cal{B} (\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{ } \rm{D}^{-} {K}^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Lambda_c^{ } \rm \overline{D}^0 {K}^{-})}
= {0.282}\pm{0.016}\pm{0.016}\pm{0.005},
\frac{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{* } \rm {D}^{-} {K}^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_c^{ } \rm {D}^{-} {K}^{-})}
= {0.460}\pm{0.052}\pm{0.028},
\frac{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{ } \rm {D}^{*-} {K}^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_c^{ } \rm {D}^{-} {K}^{-})}
= {2.261}\pm{0.202}\pm{0.129}\pm{0.046},
\frac{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{* } \rm D^{*-} K^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_c^{ } \rm D^{-} K^{-})}
= {0.896}\pm{0.137}\pm{0.066}\pm{0.018},$$
where the first uncertainties are statistical, the second are systematic, and the third are due to uncertainties in the branching fractions of intermediate particle decays. These initial observations mark the beginning of pentaquark searches in these modes, with more data set to become available following the LHCb upgrade.

Hi friends, here's the last #photo from my recent blog post (from my cold #photography - #hiking trip).
This spot was a perfect opportunity to apply ND Filters and some longexposure. I loved …

Second Chances: Finding Beauty Beyond Expectations
In this blog post, I recount a journey of redemption and unexpected beauty. After a failed attempt to capture the perfect photo at a frozen waterfall, a second chance arises. Armed with newfound determination and experience, I embark on a photographic adventure, discovering hidden opportunities and

This https://arxiv.org/abs/2401.06319 has been replaced.
initial toot: https://mastoxiv.page/@a…

Bain distortion of noble metal thin films that exhibit fcc, bct, and reoriented fcc structures
A recent experiment has reported that body-centered cubic (bcc)-structured Ag is realized by bending face-centered cubic (fcc)-structured Ag nanowires [S. Sun {\it et al}., Phys. Rev. Lett. {\bf 128}, 015701 (2022)]. However, the bcc phase has been observed only near the Ag surface. Here, we explore how the bcc phase is stabilized near the surface by compressions. Our first-principles calculations for noble metals, Cu, Ag, and Au, indicate that body-centered tetragonal (bct) rather than bcc str…

"Most of the customers flying on #Odysseus are getting the data they paid for," Intuitive Machines told a visitor today: https://arstechnica.com/space/2024/02/it-turns-out-that-odysseus-landed-on-the-moon-without-any-altimetry-data/ - "Odysseus flew all the way to the Moon on its very first time out and made a soft landing. It has been phoning home ever since, sending a rich stream of data." Oh, and contrary to earlier reports NASA's Navigation Doppler Lidar played *no* role in the landing as in the end its data could not be processed in real-time by Nova-C's computer.

This https://arxiv.org/abs/2307.16491 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

On solvability of a time-fractional semilinear heat equation, and its quantitative approach to the classical counterpart
We are concerned with the following time-fractional semilinear heat equation in the $N$-dimensional whole space ${\bf R}^N$ with $N \geq 1$. \[ {\rm (P)}_α\qquad \partial_t^αu -Δu = u^p,\quad t>0,\,\,\, x\in{\bf R}^N, \qquad u(0) = μ\quad \mbox{in}\quad {\bf R}^N, \] where $\partial_t^α$ denotes the Caputo derivative of order $α\in (0,1)$, $p>1$, and $μ$ is a nonnegative Radon measure on ${\bf R}^N$. The case $α=1$ formally gives the Fujita-type equation (P)$_1$ \ $\partial_…

This https://arxiv.org/abs/2402.16776 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

On the length of directed paths in digraphs
Thomassé conjectured the following strengthening of the well-known Caccetta-Haggkvist Conjecture: any digraph with minimum out-degree $δ$ and girth $g$ contains a directed path of length $δ(g-1)$. Bai and Manoussakis gave counterexamples to Thomassé's conjecture for every even $g\geq 4$. In this note, we first generalize their counterexamples to show that Thomassé's conjecture is false for every $g\geq 4$. We also obtain the positive result that any digraph with minimum out-degree $δ$ and…

This https://arxiv.org/abs/2307.16491 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

On solvability of a time-fractional semilinear heat equation, and its quantitative approach to the classical counterpart
We are concerned with the following time-fractional semilinear heat equation in the $N$-dimensional whole space ${\bf R}^N$ with $N \geq 1$. \[ {\rm (P)}_α\qquad \partial_t^αu -Δu = u^p,\quad t>0,\,\,\, x\in{\bf R}^N, \qquad u(0) = μ\quad \mbox{in}\quad {\bf R}^N, \] where $\partial_t^α$ denotes the Caputo derivative of order $α\in (0,1)$, $p>1$, and $μ$ is a nonnegative Radon measure on ${\bf R}^N$. The case $α=1$ formally gives the Fujita-type equation (P)$_1$ \ $\partial_…

As I just posted one of the photos of the day anyways, I thought I could share a bit of a background story with you as well.
A frosty and chill day - but I went there alone as I wanted to focus more on #photography than just #hiking the summit.

Embracing the Elements: A Frosty Photo Journey
Embark on a chilly adventure with me as I navigate the brisk winds and icy terrain of a winter hike. Join me as I brave the elements, capturing the raw beauty of snow-laden landscapes and gusty summits through the lens of my camera.

As I just posted one of the photos of the day anyways, I thought I could share a bit of a background story with you as well.
A frosty and chill day - but I went there alone as I wanted to focus more on #photography than just #hiking the summit.

Embracing the Elements: A Frosty Photo Journey
Embark on a chilly adventure with me as I navigate the brisk winds and icy terrain of a winter hike. Join me as I brave the elements, capturing the raw beauty of snow-laden landscapes and gusty summits through the lens of my camera.