Eiko Evers, Nataliia E. Kopteva, Vitalie Nedelea, Andrei Kors, Ranbir Kaur, Johann Peter Reithmaier, Mohamed Benyoucef, Manfred Bayer, Alex Greilich
Measurements of the longitudinal and transverse spin relaxation times of holes in an ensemble of vertically tunnel‐coupled self‐assembled InAs/InAlGaAs quantum dots (QDs), emitting in the telecom spectral range, are reported. The spin coherence is determined using the spin mode‐locking method in the inhomogeneous ensemble of QDs. Modeling the signal allows us to extract the hole spin coherence time to be in the range of μs. The longitudinal spin relaxation time μs is measured using the spin inertia method. The parameters investigated allow us to suggest that the main relaxation mechanism at low magnetic fields is related to the electron–hole spin exchange.
{"title":"Hole Spin Coherence in InAs/InAlGaAs Self‐Assembled Quantum Dots Emitting at Telecom Wavelengths","authors":"Eiko Evers, Nataliia E. Kopteva, Vitalie Nedelea, Andrei Kors, Ranbir Kaur, Johann Peter Reithmaier, Mohamed Benyoucef, Manfred Bayer, Alex Greilich","doi":"10.1002/pssb.202400174","DOIUrl":"https://doi.org/10.1002/pssb.202400174","url":null,"abstract":"Measurements of the longitudinal and transverse spin relaxation times of holes in an ensemble of vertically tunnel‐coupled self‐assembled InAs/InAlGaAs quantum dots (QDs), emitting in the telecom spectral range, are reported. The spin coherence is determined using the spin mode‐locking method in the inhomogeneous ensemble of QDs. Modeling the signal allows us to extract the hole spin coherence time to be in the range of μs. The longitudinal spin relaxation time μs is measured using the spin inertia method. The parameters investigated allow us to suggest that the main relaxation mechanism at low magnetic fields is related to the electron–hole spin exchange.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"13 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189063","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}
Yang Dai, Ruosong Yuan, Yukun Li, Leiyu Gao, Yiting Zhang, Pengzhan Wang, Yunyao Zhang, Xiaoyi Lei, Han Zhang, Wu Zhao
The THz photoresponse of four different structures of N‐ and Ga‐polar AlGaN/GaN plasma wave high‐electron‐mobility transistors (HEMTs) has been comparatively investigated. Based on these results, an improved N‐polar plasma wave HEMT detector is proposed: an AlGaN cap layer is introduced in the standard N‐polar HEMT, so as to obtain a lower gate leakage current, thus improving the operating characteristics of plasma wave HEMT. The results show that the responsivity of the improved N‐polar HEMT obtains a significant improvement and as the Al component of AlGaN cap layer increases, the noise equivalent power of the improved N‐polar HEMT has also been optimized.
我们对四种不同结构的 N 极和 Ga 极 AlGaN/GaN 等离子体波高电子迁移率晶体管（HEMT）的太赫兹光响应进行了比较研究。根据这些结果，提出了一种改进的 N 极等离子体波 HEMT 检测器：在标准 N 极 HEMT 中引入 AlGaN 盖层，以获得更低的栅极漏电流，从而改善等离子体波 HEMT 的工作特性。结果表明，改进型 N 极 HEMT 的响应率得到了显著提高，而且随着 AlGaN 盖层中 Al 成分的增加，改进型 N 极 HEMT 的噪声等效功率也得到了优化。
{"title":"Nonresonant Terahertz Detector Based on Improved N‐Polar AlGaN/GaN Plasma Wave High‐Electron‐Mobility Transistors","authors":"Yang Dai, Ruosong Yuan, Yukun Li, Leiyu Gao, Yiting Zhang, Pengzhan Wang, Yunyao Zhang, Xiaoyi Lei, Han Zhang, Wu Zhao","doi":"10.1002/pssb.202400055","DOIUrl":"https://doi.org/10.1002/pssb.202400055","url":null,"abstract":"The THz photoresponse of four different structures of N‐ and Ga‐polar AlGaN/GaN plasma wave high‐electron‐mobility transistors (HEMTs) has been comparatively investigated. Based on these results, an improved N‐polar plasma wave HEMT detector is proposed: an AlGaN cap layer is introduced in the standard N‐polar HEMT, so as to obtain a lower gate leakage current, thus improving the operating characteristics of plasma wave HEMT. The results show that the responsivity of the improved N‐polar HEMT obtains a significant improvement and as the Al component of AlGaN cap layer increases, the noise equivalent power of the improved N‐polar HEMT has also been optimized.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"47 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189092","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}
Excitons are expected to be a high‐efficiency emission source in UV light‐emitting devices. However, the damping of the excitonic laser oscillation has been reported under conditions where the excitonic states are expected to be populated in the conventional theory. In order to understand the exciton dynamics under the thermal nonequilibrium state, a theoretical model including various energy species in semiconductors such as electrons, phonons, and photons is required. Herein, a 2D phononic–excitonic–radiative model is constructed to analyze the exciton dynamics in a 2D system. 2D excitons with four principal quantum number states and the continuum in the lowest energy level of the AlN/GaN/AlN quantum wells are considered. It is found that the 2D phonon significantly augments the excitation transition rate. When the high recombination rate corresponding to stimulated emission is considered, the exciton binding energy of 108 meV is not enough to reduce the population in the high‐order discreet states and the continuum states, while the binding energy of 215 meV corresponding to the one monolayer GaN has an advantage of reducing these populations. The analysis of population flux has an advantage in discussing the increase in the kinetic energy transfer to the 1S exciton.
{"title":"Advantages of Ultrathin AlN/GaN/AlN Quantum Wells for Excitonic Population Distribution and Transition Features Studied by Phononic–Excitonic–Radiative Model","authors":"Masaya Chizaki, Yoshihiro Ishitani","doi":"10.1002/pssb.202400038","DOIUrl":"https://doi.org/10.1002/pssb.202400038","url":null,"abstract":"Excitons are expected to be a high‐efficiency emission source in UV light‐emitting devices. However, the damping of the excitonic laser oscillation has been reported under conditions where the excitonic states are expected to be populated in the conventional theory. In order to understand the exciton dynamics under the thermal nonequilibrium state, a theoretical model including various energy species in semiconductors such as electrons, phonons, and photons is required. Herein, a 2D phononic–excitonic–radiative model is constructed to analyze the exciton dynamics in a 2D system. 2D excitons with four principal quantum number states and the continuum in the lowest energy level of the AlN/GaN/AlN quantum wells are considered. It is found that the 2D phonon significantly augments the excitation transition rate. When the high recombination rate corresponding to stimulated emission is considered, the exciton binding energy of 108 meV is not enough to reduce the population in the high‐order discreet states and the continuum states, while the binding energy of 215 meV corresponding to the one monolayer GaN has an advantage of reducing these populations. The analysis of population flux has an advantage in discussing the increase in the kinetic energy transfer to the 1<jats:italic>S</jats:italic> exciton.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"22 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189095","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}
Xuelin Li, Zhuangzhuang Li, Zhuoyu Guo, Jiahui Lin, Yue Zhou, Zonglai Mo, Jun Li
Herein, a series of gradient designs are carried out to enhance further the energy absorption capacity of a novel star honeycomb. These include unidirectional and bidirectional gradient designs along the impact direction, while the gradient changes in the non‐impact direction are considered. Via the coupling of bidirectional and unidirectional directions, a combined gradient evolution method is further proposed. The in‐plane compression characteristics of these gradient honeycombs are systematically revealed based on the validated finite element method at low‐, medium‐, and high‐velocity impacts, respectively. The results show that honeycombs with gradient variations in the impact direction are realized as localized modes under both low‐ and medium‐velocity impacts, while honeycombs with gradient design only in the non‐impact direction exhibited global modes and “local + global” modes, respectively; under high‐speed impacts, honeycombs with gradient configurations in the non‐impact direction showed stepped layer‐by‐layer collapses, whereas honeycombs with gradient evolutions only in the impact direction collapsed in I‐shaped layers. Besides, the increase in compressive strength and specific energy absorption of honeycomb with combined gradient configuration can be up to 38.1% and 67.9%. This article provides a new idea of honeycomb gradient evolution, which can provide a reference for improving the energy‐absorption capacity of honeycombs.
{"title":"On the Study of Thickness Gradients in Novel Star Honeycombs: Classical and Combinatorial Designs","authors":"Xuelin Li, Zhuangzhuang Li, Zhuoyu Guo, Jiahui Lin, Yue Zhou, Zonglai Mo, Jun Li","doi":"10.1002/pssb.202400295","DOIUrl":"https://doi.org/10.1002/pssb.202400295","url":null,"abstract":"Herein, a series of gradient designs are carried out to enhance further the energy absorption capacity of a novel star honeycomb. These include unidirectional and bidirectional gradient designs along the impact direction, while the gradient changes in the non‐impact direction are considered. Via the coupling of bidirectional and unidirectional directions, a combined gradient evolution method is further proposed. The in‐plane compression characteristics of these gradient honeycombs are systematically revealed based on the validated finite element method at low‐, medium‐, and high‐velocity impacts, respectively. The results show that honeycombs with gradient variations in the impact direction are realized as localized modes under both low‐ and medium‐velocity impacts, while honeycombs with gradient design only in the non‐impact direction exhibited global modes and “local + global” modes, respectively; under high‐speed impacts, honeycombs with gradient configurations in the non‐impact direction showed stepped layer‐by‐layer collapses, whereas honeycombs with gradient evolutions only in the impact direction collapsed in I‐shaped layers. Besides, the increase in compressive strength and specific energy absorption of honeycomb with combined gradient configuration can be up to 38.1% and 67.9%. This article provides a new idea of honeycomb gradient evolution, which can provide a reference for improving the energy‐absorption capacity of honeycombs.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"23 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189096","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}
Reflectance anisotropy spectroscopy (RAS) is applied to investigate GaAsBi samples grown by molecular beam epitaxy on (001)‐oriented GaAs substrates with GaAs or InGaAs buffer layers, resulting in nearly lattice‐matched or compressive strain conditions, with Bi concentration in the alloy in the range 2–5%. These new samples allow to bridge the gap in the Bi concentration values of previous RAS experiments (C. Goletti et al., Appl. Phys. Lett. 2022, 120, 031902), confirming the [110]‐polarized Bi‐related anisotropy in optical spectra below 3 eV and the linear dependence of its amplitude on Bi concentration. The characterization of the grown GaAsBi samples by X‐Ray diffraction and transmission electron microscopy clearly demonstrates the presence of CuPt‐like ordering in the bulk. CuPt structure is the primary origin of the optical anisotropy measured by RAS and by polarized photoluminescence, due to the anisotropic strain produced in the bulk crystal lattice. The lineshape of the RAS spectra above 3 eV, with its overall and characteristic positive convexity, confirms this conclusion.
{"title":"Bismuth Ordering and Optical Anisotropy in GaAsBi Alloys","authors":"Ilaria Tomei, Tadas Paulauskas, Vaidas Pačebutas, Sandra Stanionyte, Filippo Pierucci, Beatrice Bonanni, Anna Sgarlata, Massimo Fanfoni, Claudio Goletti","doi":"10.1002/pssb.202400352","DOIUrl":"https://doi.org/10.1002/pssb.202400352","url":null,"abstract":"Reflectance anisotropy spectroscopy (RAS) is applied to investigate GaAsBi samples grown by molecular beam epitaxy on (001)‐oriented GaAs substrates with GaAs or InGaAs buffer layers, resulting in nearly lattice‐matched or compressive strain conditions, with Bi concentration in the alloy in the range 2–5%. These new samples allow to bridge the gap in the Bi concentration values of previous RAS experiments (C. Goletti et al., <jats:italic>Appl. Phys. Lett.</jats:italic> 2022, <jats:italic>120</jats:italic>, 031902), confirming the [110]‐polarized Bi‐related anisotropy in optical spectra below 3 eV and the linear dependence of its amplitude on Bi concentration. The characterization of the grown GaAsBi samples by X‐Ray diffraction and transmission electron microscopy clearly demonstrates the presence of CuPt‐like ordering in the bulk. CuPt structure is the primary origin of the optical anisotropy measured by RAS and by polarized photoluminescence, due to the anisotropic strain produced in the bulk crystal lattice. The lineshape of the RAS spectra above 3 eV, with its overall and characteristic positive convexity, confirms this conclusion.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"161 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189091","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}
Structural phase transitions are accompanied by a movement of one nucleus (or a few) in the crystallographic unit cell. If the nucleus movement is continuous, a second‐order phase transition without latent heat results, whereas an abrupt nucleus displacement indicates a first‐order phase transition with accompanying latent heat. Herein, a Hamiltonian including electron–phonon coupling (EPC) as proposed by Kristoffel and Konsel is taken. Contrary to their treatment, both the kinetic energy of the nucleus and its position are treated. The interaction of the many‐electron system with the single nucleus is taken into account by the Born–Oppenheimer approximation and perturbative expressions for the free energies are derived. The nuclei corrections due to the entangled electrons are found to be minor, but highlight the importance of the symmetry breaking at low temperature. Furthermore the free energy for a canonical ensemble is computed, whereas Kristoffel and Konsel use a grand canonical ensemble, which allows to derive more stringent bounds on the free energy. For the zero‐order nucleus correction, the shift of the phase transition temperature by evaluating the free energy is deduced.
{"title":"Corrections of Electron–Phonon Coupling for Second‐Order Structural Phase Transitions","authors":"Mario Graml, Kurt Hingerl","doi":"10.1002/pssb.202400139","DOIUrl":"https://doi.org/10.1002/pssb.202400139","url":null,"abstract":"Structural phase transitions are accompanied by a movement of one nucleus (or a few) in the crystallographic unit cell. If the nucleus movement is continuous, a second‐order phase transition without latent heat results, whereas an abrupt nucleus displacement indicates a first‐order phase transition with accompanying latent heat. Herein, a Hamiltonian including electron–phonon coupling (EPC) as proposed by Kristoffel and Konsel is taken. Contrary to their treatment, both the kinetic energy of the nucleus and its position are treated. The interaction of the many‐electron system with the single nucleus is taken into account by the Born–Oppenheimer approximation and perturbative expressions for the free energies are derived. The nuclei corrections due to the entangled electrons are found to be minor, but highlight the importance of the symmetry breaking at low temperature. Furthermore the free energy for a canonical ensemble is computed, whereas Kristoffel and Konsel use a grand canonical ensemble, which allows to derive more stringent bounds on the free energy. For the zero‐order nucleus correction, the shift of the phase transition temperature by evaluating the free energy is deduced.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"10 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189094","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}
Monoclinic VO2, a semiconductor with a narrow bandgap, is highly suitable for infrared (IR) spectrum utilization. The electrical and optical properties of VO2 doped with X are thoroughly examined. Specifically, Mg doping decreases the formation of V–V dimers. The presence of the 3d orbitals of the V atoms and the 2s orbital of the Mg atom leads to a decrease in the bandgap. This leads to an absorption peak of 104 in the mid‐infrared (mid‐IR) range, resulting in an optical absorption that is approximately ten times greater than that of pure VO2. As a result, it becomes simpler to detect. Notably, the responsiveness of the system doped with Mg to IR light increases. VO2 significantly increases the photocurrent density, with a 1000‐fold increase in the mid‐IR region and a tenfold increase in the near‐IR region. This finding provides a theoretical basis for empirically exploring VO2 in IR technology.
{"title":"Modulation of the Electronic Structure and Optical Properties of VO2 by Doping with X (X = Be, Mg, Al, Ga)","authors":"Dengrui Zhao, Dong Wei, Gaofu Guo, Heng Yu, Yifei Wei, Yaqiang Ma, Yanan Tang, Xianqi Dai","doi":"10.1002/pssb.202400253","DOIUrl":"https://doi.org/10.1002/pssb.202400253","url":null,"abstract":"Monoclinic VO<jats:sub>2</jats:sub>, a semiconductor with a narrow bandgap, is highly suitable for infrared (IR) spectrum utilization. The electrical and optical properties of VO<jats:sub>2</jats:sub> doped with X are thoroughly examined. Specifically, Mg doping decreases the formation of V–V dimers. The presence of the 3<jats:italic>d</jats:italic> orbitals of the V atoms and the 2<jats:italic>s</jats:italic> orbital of the Mg atom leads to a decrease in the bandgap. This leads to an absorption peak of 10<jats:sup>4</jats:sup> in the mid‐infrared (mid‐IR) range, resulting in an optical absorption that is approximately ten times greater than that of pure VO<jats:sub>2</jats:sub>. As a result, it becomes simpler to detect. Notably, the responsiveness of the system doped with Mg to IR light increases. VO<jats:sub>2</jats:sub> significantly increases the photocurrent density, with a 1000‐fold increase in the mid‐IR region and a tenfold increase in the near‐IR region. This finding provides a theoretical basis for empirically exploring VO<jats:sub>2</jats:sub> in IR technology.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"14 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189093","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}
Semiconductor nanoholes have garnered significant interest due to their unique nanotopological structures, which can result in distinct physicochemical characteristics. This study delves into the properties of crystal vibrations in nanohole structures. The analytic Fröhlich phonon state and dispersion relationship in wurtzite nanoholes, with circular and square cross sections (CS), are derived using the macroscopic dielectric continuum model. It is found that two types of phonon modes, surface optical (SO) and half‐space (HS) modes, coexist in wurtzite nitride nanohole structures. These phonon modes and their dispersive behaviors in nanoholes significantly differ from those in nanowires due to the different nanotopological structures. Furthermore, the Fröhlich electron–phonon interaction Hamiltonians for SO and HS phonon modes in nanoholes are obtained based on a field quantization scheme. Numerical calculations on wurtzite AlN nanoholes reveal that the shape of the CS has a remarkable influence on the dispersive spectra of SO and HS phonon modes. Additionally, it is found that the dielectric medium significantly affects the dispersive features of SO modes, while its influence on the dispersive behavior of HS modes is negligible. The profound physical mechanisms behind these observations are deeply analyzed.
半导体纳米孔因其独特的纳米拓扑结构而备受关注，这种结构可产生独特的物理化学特性。本研究深入探讨了纳米孔结构中的晶体振动特性。利用宏观介电连续模型推导了具有圆形和方形横截面（CS）的沃特兹体纳米孔中的解析弗洛里希声子状态和频散关系。研究发现，在钨氮化物纳米孔结构中，表面光（SO）和半空间（HS）两种声子模式共存。由于纳米拓扑结构不同，纳米孔中的这些声子模式及其色散行为与纳米线中的声子模式及其色散行为有很大不同。此外，基于场量化方案，还得到了纳米孔中 SO 和 HS 声子模式的 Fröhlich 电子-声子相互作用哈密顿。对晶圆氮化铝纳米孔的数值计算表明，CS 的形状对 SO 和 HS 声子模式的色散光谱有显著影响。此外，研究还发现介电介质对 SO 模式的色散特征有显著影响，而对 HS 模式色散行为的影响则可以忽略不计。研究深入分析了这些观察结果背后的深刻物理机制。
{"title":"Dispersive Spectra of Fröhlich Phonon Modes in Wurtzite Nitride Nanoholes with Circular and Square Cross Sections","authors":"Li Zhang, Guanghui Wang, Xianli Liu, Qi Wang","doi":"10.1002/pssb.202400197","DOIUrl":"https://doi.org/10.1002/pssb.202400197","url":null,"abstract":"Semiconductor nanoholes have garnered significant interest due to their unique nanotopological structures, which can result in distinct physicochemical characteristics. This study delves into the properties of crystal vibrations in nanohole structures. The analytic Fröhlich phonon state and dispersion relationship in wurtzite nanoholes, with circular and square cross sections (CS), are derived using the macroscopic dielectric continuum model. It is found that two types of phonon modes, surface optical (SO) and half‐space (HS) modes, coexist in wurtzite nitride nanohole structures. These phonon modes and their dispersive behaviors in nanoholes significantly differ from those in nanowires due to the different nanotopological structures. Furthermore, the Fröhlich electron–phonon interaction Hamiltonians for SO and HS phonon modes in nanoholes are obtained based on a field quantization scheme. Numerical calculations on wurtzite AlN nanoholes reveal that the shape of the CS has a remarkable influence on the dispersive spectra of SO and HS phonon modes. Additionally, it is found that the dielectric medium significantly affects the dispersive features of SO modes, while its influence on the dispersive behavior of HS modes is negligible. The profound physical mechanisms behind these observations are deeply analyzed.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"12 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189097","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}
Joseph N. Grima, Dario Cerasola, James N. Grima‐Cornish, Michelle Vella Wood, Nadia Portelli, Darren Sillato, Marilyn Casha, Alfred Gatt, Tonio P. Agius, Cynthia Formosa, Daphne Attard
On‐water rowing is a sport where participants make extensive, powerful, and complex repetitive movements with their wrists to pull and feather (twist) the oar. Herein, the aim is to assess the frequency and perceived causes of wrist and forearm pain in rowers and, in particular, assess whether there are any possible mechanical issues that could be addressed through the use of auxetic technology. Through an online survey of 145 on‐water rowers, it is found that 33.8% of the rowers reported wrist or forearm pain arising from rowing. The majority (67.3%) consider over‐gripping to be the cause while one out of five associated it with periods of tension and anxiety, which also led them to over‐grip. This indicates that rowing handles could benefit from the use of mechanical metamaterials, auxetics in particular, owing to their anomalous manner in how they deform when subjected to mechanical deformations. Moreover, given the rise in popularity of coastal rowing, which will become an Olympic discipline alongside classic rowing as from the 2028 Los Angeles Olympic Games, the potential use of auxetics in the manufacture of protective gear for use in coastal rowing is also discussed.
{"title":"On Wrist and Forearm Pain Experienced by Rowers: Can Mechanical Metamaterials Make Rowing and Coastal Rowing Safer?","authors":"Joseph N. Grima, Dario Cerasola, James N. Grima‐Cornish, Michelle Vella Wood, Nadia Portelli, Darren Sillato, Marilyn Casha, Alfred Gatt, Tonio P. Agius, Cynthia Formosa, Daphne Attard","doi":"10.1002/pssb.202400289","DOIUrl":"https://doi.org/10.1002/pssb.202400289","url":null,"abstract":"On‐water rowing is a sport where participants make extensive, powerful, and complex repetitive movements with their wrists to pull and feather (twist) the oar. Herein, the aim is to assess the frequency and perceived causes of wrist and forearm pain in rowers and, in particular, assess whether there are any possible mechanical issues that could be addressed through the use of auxetic technology. Through an online survey of 145 on‐water rowers, it is found that 33.8% of the rowers reported wrist or forearm pain arising from rowing. The majority (67.3%) consider over‐gripping to be the cause while one out of five associated it with periods of tension and anxiety, which also led them to over‐grip. This indicates that rowing handles could benefit from the use of mechanical metamaterials, auxetics in particular, owing to their anomalous manner in how they deform when subjected to mechanical deformations. Moreover, given the rise in popularity of coastal rowing, which will become an Olympic discipline alongside classic rowing as from the 2028 Los Angeles Olympic Games, the potential use of auxetics in the manufacture of protective gear for use in coastal rowing is also discussed.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"45 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224499","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}
Lu Lv, Yaoyao Ma, Qinghua Zhou, Wenhua Liu, Yuhang Zhang, Huiyuan Chen, Wei Hu
Herein, a theoretical study on Nb‐doped LiNiO2 cathode materials for Li‐ion batteries is performed based on density functional theory within the projector augmented wave method. Due to the stronger NbO interaction, the Ni‐rich cathode modified by Nb has better electronic conductivity, higher potential, and larger O‐vacancy formation energy. During the charging and discharging process, Nb doping can reduce the lattice distortion, which is conducive to improve the cycle performance of the electrode. This work provides a new insight into the atomic configuration and the origin of the performance enhancement for Nb‐doped LiNiO2 cathode and is a necessary complement to the experiment, thus helpful for rational design and manufacture of high‐performance Ni‐rich cathode materials.
本文基于投影增强波法中的密度泛函理论，对用于锂离子电池的掺铌 LiNiO2 阴极材料进行了理论研究。由于 NbO 的相互作用更强，经 Nb 修饰的富镍阴极具有更好的电子传导性、更高的电位和更大的 O 空位形成能。在充放电过程中，掺杂 Nb 可以减少晶格畸变，有利于提高电极的循环性能。该研究对掺杂 Nb 的 LiNiO2 阴极的原子构型和性能提升的起源有了新的认识，是对实验的必要补充，有助于高性能富 Ni 阴极材料的合理设计和制造。
{"title":"Niobium Modification in Ni‐Rich Cathode Materials for Li‐Ion Batteries: Insights from Ab Initio Calculations","authors":"Lu Lv, Yaoyao Ma, Qinghua Zhou, Wenhua Liu, Yuhang Zhang, Huiyuan Chen, Wei Hu","doi":"10.1002/pssb.202400242","DOIUrl":"https://doi.org/10.1002/pssb.202400242","url":null,"abstract":"Herein, a theoretical study on Nb‐doped LiNiO<jats:sub>2</jats:sub> cathode materials for Li‐ion batteries is performed based on density functional theory within the projector augmented wave method. Due to the stronger NbO interaction, the Ni‐rich cathode modified by Nb has better electronic conductivity, higher potential, and larger <jats:italic>O</jats:italic>‐vacancy formation energy. During the charging and discharging process, Nb doping can reduce the lattice distortion, which is conducive to improve the cycle performance of the electrode. This work provides a new insight into the atomic configuration and the origin of the performance enhancement for Nb‐doped LiNiO<jats:sub>2</jats:sub> cathode and is a necessary complement to the experiment, thus helpful for rational design and manufacture of high‐performance Ni‐rich cathode materials.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"13 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224498","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：