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So far Lauren Mason has created 234 blog entries.

Capturing 3D atomic defects and phonon localization at the 2D heterostructure interface

2D lateral and vertical heterostructures have been actively studied for fundamental interest and practical applications. Although aberration-corrected electron microscopy and scanning probe microscopy have been used to characterize a wide range of 2D heterostructures, the 3D local atomic structure and crystal defects at the heterostructure interface have thus far defied any direct experimental determination. Now, a collaborative team from UCLA, Harvard University, MIT and UC Irvine demonstrates a correlative experimental and first principles method to determine the 3D atomic positions and crystal defects in a MoS2-WSe2 heterojunction with picometer prevision and capture the localized vibrational properties at the epitaxial interface. They observe various crystal defects, including vacancies, substitutional defects, bond distortion and atomic-scale ripples, and quantitatively characterize the 3D atomic displacements and full strain tensor across the heterointerface. The experimentally measured 3D atomic coordinates, representing a metastable state of the  heterojunction, are used as direct input to first principles calculations to reveal new phonon modes localized at the heterointerface, which are corroborated by spatially resolved electron energy-loss spectroscopy. In contrast, the phonon dispersion derived from the minimum energy state of the  heterojunction is absent of the local interface phonon modes, indicating the importance of using experimental 3D atomic coordinates as direct input to better predict the properties of heterointerfaces. Looking forward, it is expected that the ability to couple the 3D atomic structures and crystal defects with the properties of heterostructure interfaces will transform materials design and engineering across different disciplines.

Revealing trimer cluster superstructures at ultrafast timescales in TaTe2

Understanding and controlling the forces that drive the formation of symmetry-broken phases in quantum materials is a key challenge in condensed matter physics. The nature of the correlated interplay between charge, spin, and lattice degrees of freedom, however, often remains hidden in equilibrium studies where adiabatic tuning masks the causal ordering of rapid interactions. This motivates the use of ultrafast electron diffraction (UED) to capture structural dynamics on intrinsic time scales, for insight into the role of atomic-scale lattice distortions and vibrational excitations in driving, stabilizing and ultimately controlling emergent phases.

In a recent publication, a STROBE team carried out the first-ever ultrafast study of tantalum telluride (TaTe2), yielding direct insight into its structural dynamics. The material exhibits unique periodic charge and lattice trimer order, which transitions from stripe-like chains into a (3×3) superstructure of trimer clusters at low temperatures. After cooling to 10 K, the thin crystalline films were optically excited and the structural dynamics was probed with the high-brightness electron bunches. Satellite peaks as well as sign changes in the complex diffraction patterns yield a fingerprint of the periodic order and structural transition. Our experiments captured the photo-induced melting of the trimer clusters in TaTe2, evidencing an ultrafast phase transition into the stripe-like phase on a ~1.4 ps time scale. Subsequently, thermalization into a hot cluster superstructure occurred. Density-functional calculations indicate that the initial quench is triggered by intra-trimer Ta charge transfer, which destabilizes the clusters unlike CDW melting in other TaX2 compounds.

Critical to this project were new methods and algorithms, enhanced microscopes and samples, advanced sample preparation as well as a unique high repetition rate ultrafast electron diffraction beamline utilized by the STROBE team from UC Berkeley, LBNL and UCLA

Congratulations to Margaret Murnane for Being Named One of the Best Female Scientists in the World in 2022

Margaret Murnane is one of five women scientists in Colorado named among the best in the world. The 1st edition of Research.com ranking of top female scientists in the world is based on data collected from Microsoft Academic Graph on 06-12-2021. Position in the ranking is based on a scientist’s general H-index. The Research.com ranking of top female scientists in the world includes leading female scientists from all major areas of science. It was based on a meticulous examination of 166,880 scientists on Google Scholar and Microsoft Academic Graph.

Congratulations to Jose Rodriguez for Receiving Tenure at UCLA

Professor Jose Rodriguez received tenure at UCLA in the Department of Chemistry and Biochemistry. Congratulations, Jose!

Prof. Jose Rodriguez received his Ph. D in Molecular Biology from UCLA in 2012. He was then a Postdoctoral Researcher at UCLA and subsequently joined the Department of Chemistry & Biochemistry as assistant professor in 2016.

Congratulations to Mary Scott for Receiving Tenure at University of California Berkeley

Professor Mary Scott received tenure at University of California Berkeley in the Department of Materials Science & Engineering. Congratulations, Mary!

Prof. Mary Scott received her Ph. D in Physics from UCLA in 2015. She was a Postdoctoral Researcher at UC Berkeley from 2015-2017 and has been a faculty scientist at Molecular Foundry, Lawrence Berkeley National Laboratory since 2017.

Postdoctoral Researcher for a new quantum imaging project: “Squeezed-Light Multimodal Nonlinear Optical Imaging of Microbe”

Squeezed-Light Multimodal Nonlinear Optical Imaging of Microbes

A new postdoctoral research opportunity is now available in the Jimenez group in JILA at the University of Colorado, Boulder. The overarching goal of this DOE-funded project, which is a collaboration with Oak Ridge National Laboratory, is to explore multimodal quantum nonlinear optical (NLO)imaging with squeezed-light for co-registered steady-state two-photon-excited fluorescence, two-photon-excited fluorescence lifetime and second-harmonic generation microscopies. The research will involve development and application of squeezed-light sources and frequency-domain fluorescence lifetime characterization techniques to imaging of bacteria, along with methods for measuring molecular cross-sections and accurately assessing the advantage of quantum imaging modalities over their corresponding classical equivalents. The Jimenez group is very interdisciplinary and our labs are well-equipped for quantum spectroscopy and molecular biophysics research. For more information contact Ralph Jimenez (rjimenez@jila.colorado.edu).

Congratulations to Margaret Murnane for Receiving the 2022 Isaac Newton Medal and Prize

Professor Margaret Murnane has received the 2022 Isaac Newton Medal and Prize for pioneering and sustained contributions to the development of ultrafast lasers and coherent X-ray sources and the use of such sources to understand the quantum nature of materials.

The discoveries of Professor Margaret Murnane in ultrafast laser and X-ray science have transformed the field, making it possible to capture and manipulate quantum dynamics on the fastest timescales relevant to atoms, molecules and materials. Her research is distinguished by its breadth and impact in developing new understanding in optical physics.

Murnane has demonstrated that it is possible to generate coherent, laser-like X-ray beams by upconverting laser light from the infrared directly into the extreme ultraviolet (EUV) and soft X-ray regions of the spectrum. Over more than 20 years, she uncovered how to harness the unique high-order harmonic generation process to create new quantum light sources. This work represents one of the most significant new fundamental developments in optical science in past decades, with a host of practical applications in understanding and imaging materials.

Congratulations to Franklin Dollar for Being Named a Fellow of the American Physical Society

Professor Franklin Dollar has been named Fellow of the American Physical Society. Dollar works to further research into high-intensity laser physics, as well as to make his field more inclusive, diverse and equitable. The honor recognizes not only Dollar’s research into high-intensity laser physics, but also his committed efforts to change the culture of his field in the realms of diversity, equity and inclusion (DEI). “The main impacts of my work are in short pulse laser interactions with matter, and their uses as radiation sources,” said Dollar. “I led a lot of early work in ion acceleration, but also have been involved with electron acceleration, positron beams, and directed neutron beams.”

Algorithm Engineer in Image Processing

KLA is seeking a motivated individual for an engineer position in world-class algorithm group within the reticle product division (RAPID).

  • This individual will utilize his/her skills in Deep learning/Machine learning, Image processing, mathematics, and software to develop algorithms to be integrated into KLA’s state of the art inspection platforms.
  • Responsibilities of this position include explore Convolution Neural Network application or Machine learning of novel database modeling and improve accuracy and computation efficiency; develop defect detection algorithms, apply image proc technique to maximize signal to noise ratio. This requires abstracting specific tasks into generic mathematic problem and finding customized algorithm solutions; balancing between rigor and practicality through comprehensive data analysis.
  • This person is expected to bring forward creative ideas, develop production code and provide support as needed. This candidate shall be able to work independently and with a project team; provide input to hardware group on image quality and error budget base on Algorithm design and performance; engage constructively with marketing on product requirements and provide training to application team.
  • This person shall possess bolts and nuts knowledge of various Deep Learning and bridge with conventional computer vision and image processing techniques. Significant experiences in C++ production software development and Deep Learning deployment on GPU platform is essential.
  • The candidate is expected to possess good oral and written communications skills to interact with other development and applications engineers daily.

Minimum Qualifications

  • Ph.D. or MS in Applied Math, EE, Computer Science or related discipline
  • PhD (with no work experience) or a MS degree + 3 years of work experience.
  • Deep Learning/Machine learning techniques for imaging applications
  • Image and signal processing
  • Linear and non-linear optimizations
  • Algorithm development with C++ & Python in Unix/Linux environment
  • Capability to formulate creative solutions through analyzing complex data
  • Good communication skills

Company Overview

KLA is a global leader in diversified electronics for the semiconductor manufacturing ecosystem. Virtually every electronic device in the world is produced using our technologies. No laptop, smartphone, wearable device, voice-controlled gadget, flexible screen, VR device or smart car would have made it into your hands without us. KLA invents systems and solutions for the manufacturing of wafers and reticles, integrated circuits, packaging, printed circuit boards and flat panel displays. The innovative ideas and devices that are advancing humanity all begin with inspiration, research and development. KLA focuses more than average on innovation and we invest 15% of sales back into R&D. Our expert teams of physicists, engineers, data scientists and problem-solvers work together with the world’s leading technology providers to accelerate the delivery of tomorrow’s electronic devices. Life here is exciting and our teams thrive on tackling really hard problems. There is never a dull moment with us.

Group/Division

With over 40 years of semiconductor process control experience, chipmakers around the globe rely on KLA to ensure that their fabs ramp next-generation devices to volume production quickly and cost-effectively. Enabling the movement towards advanced chip design, KLA’s Global Products Group (GPG), which is responsible for creating all of KLA’s metrology and inspection products, is looking for the best and the brightest research scientist, software engineers, application development engineers, and senior product technology process engineers. The RAPID division is the world leading provider of reticle inspection solutions for the semiconductor industry. The company provides inspection solutions to both the mask shops and the semiconductor fabs to ensure that lithography yields are consistently high thus enabling cost-effective manufacturing.

COVID-19 Vaccination Requirement:  Proof of full COVID-19 vaccination is required where permitted by law.  KLA will consider reasonable accommodation as provided by applicable law.  Please note that accommodation may not be possible where vaccination is required for an essential function of the position, including for international travel or customer site access.

The company offers a competitive and comprehensive benefits package including but not limited to the following:  medical, dental, vision, life, and other voluntary benefits,  401(K) including company matching, employee stock purchase program (ESPP), student debt assistance, tuition reimbursement program, financial planning benefits, employee assistance program (EAP), paid time off and paid company holidays, family care and bonding leave.

KLA is proud to be an Equal Opportunity Employer. We do not discriminate on the basis of race, religion, color, national origin, sex, gender identity, gender expression, sexual orientation, age, marital status, veteran status, disability status or any other status protected by applicable law. We will ensure that qualified individuals with disabilities are provided reasonable accommodation to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment. Please contact us at talent.acquisition@kla.com to request accommodation.

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