Article
Physics, Applied
Matias Bejide, Andre Vantomme, Nguyen Thanh Tung, Ewald Janssens
Summary: The extended two-temperature heat transfer model proposed in this study can be used to investigate the heat flow in multilayer antennas. The thermal properties of the buffer layer can control the heat flow dynamics in layered materials, and a large buffer layer electron-phonon coupling can induce non-intuitive reverse internal heat flow and transient energy retention on short timescales.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
S. Q. Jia, L. Bolzoni, T. Li, F. Yang
Summary: Cu-Cr/55 vol% diamond composites with different weight percentages of Cr additives were fabricated by hot forging, showing varied interface structures and thermal conductivities. The Cu-3Cr/55Dia composite exhibited the highest measured thermal conductivity, with a double-layered interface structure between the copper matrix and diamond particles. The modified models successfully predicted the thermal conductivity values, contributing to understanding heat transfer behavior in Cu-Cr/diamond composites.
Review
Physics, Condensed Matter
Christopher M. Stanley
Summary: The miniaturization of microelectronics has resulted in increased energy and interface density, creating new thermal resistors that prevent heat escape. Kapitza resistance has become the dominant cause of thermal resistance in microelectronics, yet remains poorly understood. This review critically examines existing literature, focusing on molecular dynamic simulations of the Si/Ge interface, and presents a research strategy to control Kapitza resistance. It proposes benchmark systems for verification and characterization of size effects, and suggests that first-principles calculations with anharmonic contributions are key to future progress.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
Article
Physics, Multidisciplinary
Junjie Chen, Zhiwei Pang
Summary: This study numerically investigates the quasi-ballistic heat conduction properties of phonons in a multi-material system and the variations of phonon mean free path with different modulation frequencies. The results indicate that the modulation frequency does not affect the effective thermal conductivity of the system, and the effect of quasi-ballistic heat conduction is noticeable even in semiconductor alloys at room temperature.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Chemistry, Physical
Tammy X. Leong, Layla N. Qasim, Robert T. Mackin, Yuchen Du, Robert A. Pascal, Igor V. Rubtsov
Summary: A method of rapidly and unidirectionally funneling high-frequency vibrational quanta over large distances using oligo(p-phenylene) chains has been discovered. The transport of high-energy vibrational quanta with speeds reaching 8.6 km/s can be controlled by tuning the degree of conjugation via electronic doping of the chain, opening avenues for developing materials with controllable energy transport properties for heat management and initiating chemical reactions remotely.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Physics, Multidisciplinary
Hai Jun Cho, Yuzhang Wu, Jiajun Qi, Yuna Kim, Hiromichi Ohta, Osamu Matsuda
Summary: In this study, superlattices are used to simulate the phonon transmission in nanostructures. It is found that the formation of mini-gaps in phononic structures affects the transmission of phonons and its mechanism in nanostructures.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Materials Science, Multidisciplinary
Hiromu Hamasaki, Takumi Kawase, Kaori Hirahara
Summary: The interface between carbon nanotubes plays a significant role in their thermal transport properties. This study investigates the anisotropic thermal properties of carbon nanotube bundles using the phase transition of Sn nanoparticles. The results reveal that the anisotropic thermal properties are not limited to high temperatures and are more pronounced at lower temperatures.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
Hengrui Yang, Weitang Li, Jiajun Ren, Zhigang Shuai
Summary: This study proposes a nearly exact method to evaluate the time-dependent current and occupation number in a molecular junction with strong electron-phonon coupling. The oscillation period and amplitude of the current are found to be dependent on the electron-phonon coupling strength and energy level alignment. A new approximation is introduced to explain the bistability phenomenon and steady currents in the strong electron-phonon coupling regime, and comparisons are made with other methods. The entropy of different orderings is also explored, and the thermal Bogoliubov transformation is used for finite-temperature analysis.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Materials Science, Multidisciplinary
K. M. Yang, Q. Li, Q. Zhang, G. S. Liu, J. J. Wang, Y. F. Yang, C. X. Guo, J. M. Ni, J. Song, J. Zhang, Y. Liu, T. X. Fan
Summary: Graphene/Copper composites hold great potential in thermal-management and information-transport applications. This study investigates the intrinsic relationship between microstructural characteristics and interface stability of different Gr/Cu interfaces. The results show that Gr/{10 0} Cu interfaces have higher defect sink capability, while Gr/{111}/{100} Cu interfaces possess both high defect sink capability and good interface stability.
Article
Chemistry, Physical
Gen Li, Bing-Zhong Hu, Wen-Hao Mao, Nuo Yang, Jing-Tao Lu
Summary: This study investigates nonequilibrium heat transport in current-carrying single-molecular junctions using machine-learning potential and molecular dynamics. The results show that single-molecular junctions with graphene electrodes generate significantly less heating than those with gold electrodes, which is attributed to the better phonon spectral overlap of graphene with molecular vibrations.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Anna Bodyakova, Arina Pilipenko, Anna Lugovskaya, Andrey Belyakov, Rustam Kaibyshev
Summary: The thermal stability of gradient microstructures in a Cu-Cr-Zr alloy subjected to ECAP was studied, showing that an increase in ECAP passes led to a decrease in recrystallization temperature. The influence of deformation microstructures and particle precipitation on recrystallization development was also discussed in the study.
Article
Materials Science, Multidisciplinary
Jixin Yang, Yongjiang Huang, Baokun Liu, Chao Guo, Jianfei Sun
Summary: The as-built Nb521 alloy fabricated by electron beam selective melting (EBSM) exhibited an increasing content of precipitates from the top to the bottom region. The precipitates mainly consisted of (Nb, Zr)C and Nb2C, which became fine and uniform with prolonged thermal balance holding time. The study results provide a solid theoretical and technological basis for the fabrication of refractory Nb-based alloy using the EBSM process.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Paul Wenk, Milena Grifoni, John Schliemann
Summary: The occurrence of a topological phase transition induced by an effective magnetic field in a two-dimensional electron gas with spin-orbit coupling and in proximity to an s-wave superconductor is demonstrated. The effective field, perpendicular to the plane, is generated by an in-plane, off-resonant ac-magnetic field or circularly polarized light. The conditions for entering the topological phase do not rely on fine parameter tuning and can be analytically evaluated. In this phase, chiral edge states generally emerge for a system in stripe geometry unless the Rashba and Dresselhaus couplings have the same magnitude. In the special case, the edge states become Majorana flat bands when driven by a magnetic field, due to the presence of chiral symmetry; the light-irradiated system is a trivial superconductor.
Article
Thermodynamics
O. Farzadian, F. Yousefi, C. Spitas, K. Kostas
Summary: In this study, non-equilibrium molecular dynamics simulations were used to investigate phonon heat transport in a two-dimensional superlattice with equal-sized domains of graphene and phagraphene. It was found that the minimum thermal conductivity occurred at a superlattice period of 12.85 nm for ribbons, with a value of 155 W/mK. The minimum thermal conductivity of graphene-phagraphene superlattices is approximately 5% of pure graphene thermal conductivity and 50% of phagraphene thermal conductivity.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Chemistry, Physical
Xiaofang Li, Chunlei Tan, Juantao Jiang, Shaoyi Wang, Fenghua Zheng, Xiaohui Zhang, Hongqiang Wang, Youguo Huang, Qingyu Li
Summary: A new electron thermal conductive route is proposed and constructed for graphene-based metal matrix composites to achieve high-efficient heat dissipation. Functionalization of graphene and deposition of specific substances onto the copper surface result in the FGr/Cu composite with superior and stable thermal conductivity at high temperatures.
Article
Materials Science, Ceramics
Ian A. Brummel, Kevin Wynne, William A. Lanford, Jon F. Ihlefeld
Summary: A combustion synthesis methodology was used to prepare perovskite Li3xLa1/3-xTaO3 lithium-ion conductors. Different lithium vapor overpressure conditions were achieved by sintering under different burial powder and cover crucible combinations. The ion conductivity was found to be influenced by the lithium content and secondary phase content in the samples.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Correction
Physics, Applied
Jon F. F. Ihlefeld, Samantha T. T. Jaszewski, Shelby S. S. Fields
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Ceramics
Alejandro Salanova, Ian A. A. Brummel, Andrey A. A. Yakovenko, Elizabeth J. J. Opila, Jon F. F. Ihlefeld
Summary: Temperature limitations in nickel-base superalloys have led to the emergence of SiC-based ceramic matrix composites as a viable replacement for gas turbine components. Rare-earth disilicate coatings have been identified as environmental barriers that can minimize hot component degradation. This study synthesized rare-earth disilicate powders and explored their phase stability and thermal expansion properties, suggesting that microstructure design and crystallographic texture are important for ensuring the thermo-mechanical robustness of the coatings.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Coatings & Films
Saadia Nasir, Walter J. Smith, Thomas E. Beechem, Stephanie Law
Summary: Bi2Se3 is a widely studied 3D topological insulator with potential applications in optics, electronics, and spintronics. When the thickness of the films decreases to less than approximately 6 nm, the top and bottom surface states couple, resulting in the opening of a small gap at the Dirac point. In the 2D limit, Bi2Se3 may exhibit quantum spin Hall states. However, growing coalesced ultrathin Bi2Se3 films with a controllable thickness and typical triangular domain morphology in the few nanometer range is challenging.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Chemistry, Multidisciplinary
Shelby S. S. Fields, Samantha T. T. Jaszewski, Megan K. K. Lenox, Jon F. F. Ihlefeld
Summary: This study introduces a method of electrode replacement to achieve electrode-independent ferroelectric and field-induced ferroelectric properties in HfxZr1-xO2 (HZO) thin films after post-metallization anneal processing. The results showed that electrode replacement can generate internal biases of different magnitudes, which affect the remanent polarization values, facilitating the implementation of these ferroelectric materials into the next generation device structures.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Md Shafkat Bin Hoque, Ian A. Brummel, Eric R. Hoglund, C. Jaymes Dionne, Kiumars Aryana, John A. Tomko, John T. Gaskins, Daniel Hirt, Sean W. Smith, Thomas Beechem, James M. Howe, Ashutosh Giri, Jon F. Ihlefeld, Patrick E. Hopkins
Summary: In this study, the effects of composition and interface density on the sound speed and thermal conductivity of amorphous aluminum nitride and aluminum oxide multilayers were investigated experimentally and numerically. It was found that the oxygen content determines the longitudinal sound speed of the multilayers, while the thermal conductivity is influenced by both interface density and oxygen content. The interfaces decrease the thermal conductivity, while the oxygen content increases it, resulting in a nearly constant thermal conductivity as a function of interface density. This study provides crucial insights into the interplay of composition and interfaces on the thermal properties of multilayers.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Physics, Applied
Antik Mallick, Megan K. Lenox, Thomas E. Beechem, Jon F. Ihlefeld, Nikhil Shukla
Summary: In this study, the mechanisms behind the limited endurance and sub-optimal stress response of (Hf,Zr)O-2 are investigated using electrical measurements and photoluminescence spectroscopy in W/Hf0.5Zr0.5O2/W capacitors. The behavior is attributed to defect levels at 0.6 eV from the conduction band edge, which can be correlated to the presence of oxygen vacancies using photoluminescence spectroscopy. This work helps to identify oxygen vacancies as the key factor responsible for the degraded endurance and stress response in (Hf,Zr)O-2 and motivates further exploration of methods to reduce oxygen vacancy concentrations without destabilizing the ferroelectric orthorhombic phase.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Coatings & Films
Peter M. Litwin, Samantha T. Jaszewski, Wendy L. Sarney, Asher C. Leff, Sergiy Krylyuk, Albert V. Davydov, Jon F. Ihlefeld, Stephen J. McDonnell
Summary: We synthesized self-intercalated Nb1+xSe2 thin films by molecular beam epitaxy. The amount of intercalation in the thin films is inversely proportional to the Se to Nb beam equivalence pressure ratio (BEPR). X-ray photoelectron spectroscopy and x-ray diffraction confirmed the growth of Nb1+xSe2 phase at BEPRs of 5:1 and greater. Electrical resistivity measurements showed an inverse relationship between BEPR and resistivity in the Nb1+xSe2 thin films. Another Nb-Se compound with a stoichiometry of similar to 1:1 was synthesized using a Se to Nb BEPR of 2:1, but it did not exhibit a layered structure.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Physics, Condensed Matter
Bishal Shrestha, Samantha T. Jaszewski, Jon F. Ihlefeld, Steve L. Wolfley, M. David Henry, Nikolas J. Podraza
Summary: Ellipsometric spectra were used to analyze polycrystalline thin film tantalum nitride (TaN) and obtain the optical constants and refractive index spectra. It was found that the optical response of both as-deposited and annealed TaN films can be described and differentiated using a parametric expression.
SURFACE SCIENCE SPECTRA
(2023)
Article
Physics, Applied
Jon F. Ihlefeld, Travis Peters, Samantha T. Jaszewski, Takanori Mimura, Benjamin L. Aronson, Susan Trolier-McKinstry
Summary: The influence of biaxial stress on the maximum and remanent polarizations of 10 nm thick hafnium zirconium oxide thin films has been studied. It was found that reducing the intrinsic strain through the application of a compressive uniaxial stress resulted in a decrease in the remanent and maximum polarizations. The observed variation in polarization with strain is consistent with strain impacting ferroelastic switching.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Jacob Minyard, Thomas E. Beechem
Summary: The material dependence of in-plane thermal conductance based on phonon-polaritons is investigated in this study. It is found that regardless of the material, the phonon-polaritons exhibit similar thermal conductance to phonons when the layers become ultrathin. A figure of merit is proposed to explain the variation in in-plane polariton thermal conductance, which is related to optical phonon energies, mode splitting, and lifetimes.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Kyle P. Kelley, Anna N. Morozovska, Eugene A. Eliseev, Yongtao Liu, Shelby S. Fields, Samantha T. Jaszewski, Takanori Mimura, Sebastian Calderon, Elizabeth C. Dickey, Jon F. Ihlefeld, Sergei V. Kalinin
Summary: Ferroelectricity in binary oxides such as hafnia and zirconia has attracted attention due to unconventional physical mechanisms and potential integration into semiconductor workflows. Recent research suggests that factors such as electrochemical boundary conditions and strain heavily influence the ferroelectric properties. The interplay between ferroelectric and structural instabilities, coupled with non-local screening, explains the emergence of these properties.
Article
Materials Science, Multidisciplinary
Megan K. Lenox, Samantha T. Jaszewski, Shelby S. Fields, Nikhil Shukla, Jon F. Ihlefeld
Summary: This study investigates the endurance of ferroelectric HfO2 through manipulating the time under field using bipolar pulses of varying pulse duration or duty cycle. The results show that increasing pulse duration leads to an increase in remanent polarization and leakage current. However, using very short pulse duration can significantly improve device endurance.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
