Physica Status Solidi B-basic Solid State Physics最新文献

{"title":"Comparison of SiNx Dielectric Layer Grown by Plasma‐Enhanced Chemical Vapor Deposition, Low‐Pressure Chemical Vapor Deposition, and Metal‐Organic Chemical Vapor Deposition in Diamond‐ and GaN‐Based Integrated Devices","authors":"Haolun Sun, Mei Wu, Ping Wang, Chao Yuan, Guoliang Ma, Ling Yang, Xiaohua Ma, Yue Hao","doi":"10.1002/pssb.202400052","DOIUrl":"https://doi.org/10.1002/pssb.202400052","url":null,"abstract":"To address the issue of heat dissipation caused by the high output power density of gallium nitride (GaN) devices, using diamond‐integrated devices is an effective solution. Recent studies have suggested that incorporating a dielectric layer, such as silicon nitride (SiN<jats:sub><jats:italic>x</jats:italic></jats:sub>), between diamond and GaN can improve adhesion while also reducing thermal boundary resistance (TBR). In this study, plasma‐enhanced chemical vapor deposition (CVD), low‐pressure CVD, and metal‐organic CVD (MOCVD) techniques are utilized to grow the SiN<jats:sub><jats:italic>x</jats:italic></jats:sub> layer. The interface behavior of diamond/SiN<jats:sub><jats:italic>x</jats:italic></jats:sub>/GaN is analyzed through scanning electron microscopy, transmission electron microscopy (TEM), scanning TEM, and energy‐dispersive X‐ray spectroscopy, while time‐domain thermoreflectance measurement is used to characterize thermal properties. After analyzing the impact of the growth dielectric layer on the interface thermal resistance of the three growth modes, it is concluded that the dielectric layer produced by the MOCVD technique exhibits a smoother surface and lower TBR compared to the other two methods. Therefore, the use of the MOCVD technique is recommended to achieve optimal thermal performance in diamond/SiN<jats:sub><jats:italic>x</jats:italic></jats:sub>/GaN systems.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141150613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time‐Resolved Optical Response of the Dicke's Model via the Nonequilibrium Green's Function Approach","authors":"Megha Gopalakrishna, Yaroslav Pavlyukh, Claudio Verdozzi","doi":"10.1002/pssb.202300576","DOIUrl":"https://doi.org/10.1002/pssb.202300576","url":null,"abstract":"Due to their conceptual appeal and computational convenience, two‐level systems (TLSs) and generalizations are used to investigate nonlinear behavior in quantum optics and assess the applicability of theoretical methods. Herein, the focus is on second‐harmonic generation (SHG) and, as system of interest, on the Dicke model, which consists of several TLSs inside an optical cavity. The main aspect addressed is the scope of nonequilibrium Green's function (NEGF) to describe the effect of inhomogeneities and electron–electron (<jats:italic>e</jats:italic>–<jats:italic>e</jats:italic>) interactions on the SHG signal. For benchmarking purposes, exact diagonalization (ED) results are also presented and discussed. SHG spectra obtained with NEGF and ED are found to be in very good mutual agreement in most situations. Furthermore, inhomogeneity in the TLS and <jats:italic>e</jats:italic>–<jats:italic>e</jats:italic> interactions reduce the SHG signal, and the reduction is stronger with inhomogeneity than with interactions. This trend is consistently noted across different (small to large) system sizes. Finally, a modified NEGF approach is proposed to account for cavity leakage, where the quantum photon fields are coupled to a bath of classical oscillators. As expected, within this mixed quantum‐classical scheme, a decrease in the intensity of the fluorescent spectra takes place depending on the entity of leakage.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141150577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Analysis for the Behavior of Beryllium and Magnesium Crystals at Ultrahigh Pressures","authors":"Nikolai A. Smirnov","doi":"10.1002/pssb.202300551","DOIUrl":"https://doi.org/10.1002/pssb.202300551","url":null,"abstract":"The article presents ab initio calculation results on the structural‐phase stability of beryllium and magnesium crystals under high and ultrahigh pressures (multiterapascal regime). Magnesium is shown to undergo a number of structural transformations which markedly reduce the crystal packing factor. As for beryllium, its high‐pressure body‐centered cubic phase remains stable even under ultrahigh pressures. Changes in the electronic structure of Be and Mg crystals under compression are analyzed and some interesting effects are revealed. Specifically, a narrow bandgap appears in the electronic structure of magnesium under pressures above 2.5 TPa. For the metals of interest, pressure‐temperature diagrams are constructed and compared with available experimental and theoretical results from other investigations.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141150605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metal–Organic Vapor Phase Epitaxy of High‐Quality GaN on Al‐Pretreated Sapphire Substrates Without Using Low‐Temperature Buffer Layers","authors":"Kodai Takemura, Takato Fukui, Yoshinobu Matsuda, Mitsuru Funato, Yoichi Kawakami","doi":"10.1002/pssb.202400043","DOIUrl":"https://doi.org/10.1002/pssb.202400043","url":null,"abstract":"Metal–organic vapor phase epitaxy of GaN on sapphire (0001) substrates without using low‐temperature (LT) buffer layers is demonstrated. The growth of GaN is achieved by pretreatment of sapphire with trimethylaluminum (TMA) at a high temperature (1050 °C) in a H<jats:sub>2</jats:sub> + N<jats:sub>2</jats:sub> gas mixture. The TMA pretreatment forms AlN, which acts as nucleation seeds for the subsequent growth of GaN at the same temperature. When AlN created by the TMA pretreatment is three‐dimensional, similar to conventional LT buffer layers, the GaN layers exhibit good structural properties such as atomically smooth surfaces and narrow X‐ray diffraction line widths, comparable to those of GaN on LT buffer layers. In addition, the growth evolution of GaN on TMA‐pretreated sapphire is similar to that on GaN or AlN LT buffer layers. These similarities between the TMA pretreatment and conventional LT buffer‐layer technologies might offer an opportunity to further generalize the heteroepitaxy growth model of GaN.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141058776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First‐Principles Investigations of Structural, Electronic, and Elastic Properties of ZrSiO3 Perovskite: Layer Dependence, Surface Termination, and Pressure Effects","authors":"Peshal Pokharel, Shashit Kumar Yadav, Nurapati Pantha, Devendra Adhikari","doi":"10.1002/pssb.202400156","DOIUrl":"https://doi.org/10.1002/pssb.202400156","url":null,"abstract":"Zirconium silicate (ZrSiO<jats:sub>3</jats:sub>) perovskite is a promising material for various technological applications. The structural, electronic, and thermodynamic properties of ZrSiO<jats:sub>3</jats:sub> perovskite are studied under different conditions, including pressure and layer configuration variations using density functional theory. The present investigation includes a thorough analysis of 2D perovskite derivatives derived from its basic 3D structure. The bulk and surface‐terminated silicon‐dominant SiO<jats:sub>2</jats:sub> and zirconium‐dominant ZrO compounds are found to be mechanically stable with an anisotropy factor above 1. The calculated indirect‐bandgap values for the ZrO termination and SiO<jats:sub>2</jats:sub> termination are found to be 2.585 and 1.639 eV, respectively. Moreover, the pore size of the SiO<jats:sub>2</jats:sub>‐terminated slab model of ZrSiO<jats:sub>3</jats:sub> is calculated to be 105.39 μm and that for ZrO‐termination to be 129.30 μm. Thus, the material considered for the study can have potential applications in bone regeneration and tissue engineering. Further, the possibilities for modifying ZrSiO<jats:sub>3</jats:sub> for uses in electrical devices, sensors, sustainable energy materials, and even biomedical applications like tissue engineering are intriguingly expanded by the present findings.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141058777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterizations of Subbandgap Optical Absorption in Undoped‐GaN and 90 nm‐Thick Al1−xInxN Thin Film on Sapphire Substrates Grown by Metal–Organic Chemical Vapor Deposition","authors":"Kouki Noda, Yuto Murakami, Hayata Toyoda, Kana Shibata, Youna Tsukada, Daichi Imai, Tetsuya Takeuchi, Makoto Miyoshi, Takao Miyajima","doi":"10.1002/pssb.202400029","DOIUrl":"https://doi.org/10.1002/pssb.202400029","url":null,"abstract":"Subbandgap optical absorption (SOA) in undoped GaN and 90 nm‐thick Al<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>In<jats:sub><jats:italic>x</jats:italic></jats:sub>N thin films grown on sapphire substrates is investigated using photothermal deflection spectroscopy (PDS) and photoluminescence (PL). An Al<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>In<jats:sub><jats:italic>x</jats:italic></jats:sub>N alloy (<jats:italic>x</jats:italic> = 0.17) is grown on a GaN/sapphire template by metal–organic chemical vapor deposition (MOCVD), and the SOA is observed using PDS. To develop an estimation method for the absorption coefficient (<jats:italic>α</jats:italic>) of SOA in GaN and Al<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>In<jats:sub><jats:italic>x</jats:italic></jats:sub>N thin films, the use of a thick GaN substrate is proposed, which is grown by hydride vapor‐phase epitaxy, as a converter of the PDS signal intensity to <jats:italic>α</jats:italic>, and the accuracies of the estimated <jats:italic>α</jats:italic> are discussed. Comparing the PDS and PL results, it is revealed that nonradiative recombination centers leading to the reduction of the near‐band‐edge PL intensity are not the dominant sources of SOAs in GaN. Other in‐gap states formed by impurities and/or their complexes with vacancy‐type defects are possible sources of a large SOA in the MOCVD‐grown GaN template. Considering the PDS results and reported peak reflectivity of Al<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>In<jats:sub><jats:italic>x</jats:italic></jats:sub>N/GaN distributed Bragg reflectors, the <jats:italic>α</jats:italic> value of sub‐100 nm‐thick Al<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>In<jats:sub><jats:italic>x</jats:italic></jats:sub>N alloy grown on GaN/sapphire template is expected to be ≈100 cm<jats:sup>−1</jats:sup> or less below 3.0 eV.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141058736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exact Analytical Solutions for the Kinks, the Solitons and the Shocks in Discrete Nonlinear Transmission Line with Nonlinear Capacitance","authors":"Eugene Kogan","doi":"10.1002/pssb.202400140","DOIUrl":"https://doi.org/10.1002/pssb.202400140","url":null,"abstract":"Discrete transmission lines constructed from ideal linear inductors and nonlinear capacitors (and possibly resistors) are studied. The localized travelling waves in the lossless transmission lines are the kinks and the solitons, the localized travelling waves in the lossy transmission lines are the dissipative kinks and the shocks. The speeds and profiles of all these waves are calculated.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141150602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced Magnetic and Dielectric Properties of YFeO3 Ceramics via Formation of Solid‐Solution with Sr2Bi4Ti5O18 and ZnSnO3 Oxides","authors":"Kolleti Venkatadri, Dudekula Zarena","doi":"10.1002/pssb.202400089","DOIUrl":"https://doi.org/10.1002/pssb.202400089","url":null,"abstract":"In the present investigation, magnetic and dielectric properties of solid‐solution formed between the YFeO<jats:sub>3</jats:sub> with the similar crystal structure of other oxide materials are focused on. Orthorhombic crystal structure of YFeO<jats:sub>3</jats:sub> (YFO), Sr<jats:sub>2</jats:sub>Bi<jats:sub>4</jats:sub>Ti<jats:sub>5</jats:sub>O<jats:sub>18</jats:sub> (SBT), and ZnSnO<jats:sub>3</jats:sub> (ZS) nanomaterials are considered to prepare the solid solutions at 1150 °C/3 h. YFO and solid solutions exhibit the orthorhombic crystal structure, which is conformed through Rietveld refinement using X‐Ray powder diffraction pattern. The decreased average grain size is observed for the solid solution (3.0 μm for YFO and ZS and 2.6 μm for YFO and SBT) when compared to YFO (3.4 μm) through scanning electron microscopy. Oxidation state of each atom/ion/element present in the YFO and solid solutions are conformed through X‐Ray photoelectron spectroscopy studies. The solid solution formed between the YFO and SBT exhibits high magnetization value (2.92 emu g<jats:sup>−1</jats:sup>) and high coercive filed (67.5 Oe) when compared to solid solution formed between the YFO and ZS (magnetization value = 2.48 emu g<jats:sup>−1</jats:sup>, and coercive filed = 46.4 Oe) and YFO (magnetization value = 1.91 emu g<jats:sup>−1</jats:sup>, and coercive filed = 61.8 Oe). High dielectric permittivity (<jats:italic>ε</jats:italic><jats:sub>r</jats:sub>), low dielectric loss (tan <jats:italic>δ</jats:italic>), and low conductivity are observed for the solid solution formed between the YFO and SBT, when compared to other materials in this study.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140934088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"1D Vertical Ferroelectricity in Functionalized Carbon/Boron Nitride Nanotubes","authors":"Dong Wang, Changsheng Song, Tingting Zhong, Menghao Wu","doi":"10.1002/pssb.202400013","DOIUrl":"https://doi.org/10.1002/pssb.202400013","url":null,"abstract":"Low‐dimensional ferroelectricity is long sought for post‐Moore nanoscale nonvolatile memory. Although a series of 2D ferroelectrics (FEs) have been experimentally confirmed in recent years, the investigations on 1D FEs are still rare. Stimulated by the experimental synthesis of single‐walled carbon/boron nitride nanotubes endohedrally doped by metal halides, our first‐principles calculations show that they can be the candidates for 1D FEs with switchable polarizations vertical to the tube axis as the inner metal halides form into polar zigzag chains. The polarization can be reversed via the migration of metal ions inside the wall, crossing a small barrier around several meV. Similar 1D vertical ferroelectricity in ternary boron carbonitride hybrid nanotubes that have already been synthesized is also predicted. In comparison, herein, polarization is switched by rolling the whole nanotube, which can be realized by applying just a local electric field induced by a tip due to its structural rigidity, which is long sought but remains challenging in current explorations on either conventional or low‐dimensional FEs.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140832965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inclined‐Strut Optimized Mechanical Metamaterials with Enhanced Compression–Torsion Conversion Efficiencies","authors":"Haitao Liu, Yanbin Wang, Wenjuan Wu","doi":"10.1002/pssb.202400050","DOIUrl":"https://doi.org/10.1002/pssb.202400050","url":null,"abstract":"Herein, two improved compression–torsion conversion (CTC) mechanical metamaterials are proposed with arrayed‐type and cylindrical shell‐type based on the optimization design of an inclined strut. Compared with the original design, improvements in CTC performance can be achieved by optimization of the strut shape in the feasible region. The CTC properties of the optimized metamaterials are studied by theoretical calculations, finite‐element simulations, and experiments. The effects of the shape coefficients of the S‐strut on the optimization efficiencies are discussed. The optimized structures significantly improve the mechanical properties of the CTC mechanical metamaterials. The optimized S‐strut metamaterials are increased by more than 25% higher CTC efficiencies than the original structures. The structures have improved CTC properties and are closer to the application. In addition, the proposed S‐strut mechanical metamaterials have a promising application in the aerospace field.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140811653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}