Pub Date : 2023-06-11DOI: 10.1080/14786435.2023.2221044
Yong Pan, Xiaowen Chen
ABSTRACT Although TiAl3 is widely used in various high-temperature fields, the adjustment of the balance between the strength and ductility of the tetragonal TiAl3 remains a challenge. To solve the key problem, here, we apply the first-principles method to study the influence of four transition metals (TM = V, Cr and Mo) on the mechanical properties of the tetragonal TiAl3. The structural stability of the TM-alloyed TiAl3 is examined by the impurity formation energy and phonon dispersion. The calculated results show that the TM-doped TiAl3 is stable at the ground state. In particular, the Mo-alloyed TiAl3 has better thermodynamic stability than the other TM-alloyed TiAl3. Importantly, the alloyed elements enhance the bulk modulus of TiAl3 because the alloyed elements improve the electronic hybridisation between the Ti atom and the Al atom. Here, the Mo-alloyed TiAl3 has the highest bulk modulus among the four TM-alloyed TiAl3. Furthermore, it is found that the alloyed elements improve the ductility of TiAl3.
{"title":"Adjusting the balance between strength and ductile of the tetragonal TiAl3 alloy: a first-principles investigation","authors":"Yong Pan, Xiaowen Chen","doi":"10.1080/14786435.2023.2221044","DOIUrl":"https://doi.org/10.1080/14786435.2023.2221044","url":null,"abstract":"ABSTRACT Although TiAl3 is widely used in various high-temperature fields, the adjustment of the balance between the strength and ductility of the tetragonal TiAl3 remains a challenge. To solve the key problem, here, we apply the first-principles method to study the influence of four transition metals (TM = V, Cr and Mo) on the mechanical properties of the tetragonal TiAl3. The structural stability of the TM-alloyed TiAl3 is examined by the impurity formation energy and phonon dispersion. The calculated results show that the TM-doped TiAl3 is stable at the ground state. In particular, the Mo-alloyed TiAl3 has better thermodynamic stability than the other TM-alloyed TiAl3. Importantly, the alloyed elements enhance the bulk modulus of TiAl3 because the alloyed elements improve the electronic hybridisation between the Ti atom and the Al atom. Here, the Mo-alloyed TiAl3 has the highest bulk modulus among the four TM-alloyed TiAl3. Furthermore, it is found that the alloyed elements improve the ductility of TiAl3.","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"50 1","pages":"1577 - 1591"},"PeriodicalIF":1.6,"publicationDate":"2023-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78381256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-08DOI: 10.1080/14786435.2023.2220092
L. Kong, Z. Xing, Y. Shu, Q. Duan, Z. Zhang, P. Li
ABSTRACT Temperature and frequency are significant extrinsic factors that influence the cyclic deformation behaviour of face-centred cubic crystal (fcc) single crystals. For Cu single crystals, an increase in temperature causes the disappearance of the plateau region in the cyclic stress–strain (CSS) curves and a significant decrease in the saturation resolved shear stress at low strain amplitudes. This is attributed to the enlargement of the space between Persistent Slip Band (PSB) ladders, resulting in a lower volume fraction of the rungs in PSBs, leading to a lower saturation shear stress. Conversely, an increase in frequency does not affect the appearance of the plateau behaviour in CSS curves, but it slightly increases the corresponding plateau stress. This is because a higher frequency increases the probability of interaction between edge dislocations, leading to an increase in the local flow stress in the rungs, ultimately resulting in an increment of the saturation stress.
{"title":"Effects of temperature and frequency on cyclic deformation behaviours of Cu single crystals","authors":"L. Kong, Z. Xing, Y. Shu, Q. Duan, Z. Zhang, P. Li","doi":"10.1080/14786435.2023.2220092","DOIUrl":"https://doi.org/10.1080/14786435.2023.2220092","url":null,"abstract":"ABSTRACT Temperature and frequency are significant extrinsic factors that influence the cyclic deformation behaviour of face-centred cubic crystal (fcc) single crystals. For Cu single crystals, an increase in temperature causes the disappearance of the plateau region in the cyclic stress–strain (CSS) curves and a significant decrease in the saturation resolved shear stress at low strain amplitudes. This is attributed to the enlargement of the space between Persistent Slip Band (PSB) ladders, resulting in a lower volume fraction of the rungs in PSBs, leading to a lower saturation shear stress. Conversely, an increase in frequency does not affect the appearance of the plateau behaviour in CSS curves, but it slightly increases the corresponding plateau stress. This is because a higher frequency increases the probability of interaction between edge dislocations, leading to an increase in the local flow stress in the rungs, ultimately resulting in an increment of the saturation stress.","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"29 1","pages":"1531 - 1552"},"PeriodicalIF":1.6,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87092617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1080/14786435.2023.2215549
Gaobing Wei, Hongxian Xie, G. Lu
ABSTRACT Anti-twin has been experimentally observed in body-centered cubic nanopillars, which naturally raises the reconsideration of twinning pathways at the crack tips. Using molecular dynamics simulations, we find that shuffling anti-twinning and twinning pathways appear simultaneously at the crack tip; while only twinning pathway appears at the crack tip. By analysing the shear stress distribution of the two crack models, we reveal that the specific twinning pathway is determined by the direction relationship between the anti-twinning/twinning slip system and the butterfly-like shear stress fields. This study deepens our understanding of anti-twin and extends the knowledge about the twin formation mechanisms at the crack tips of body-centered cubic metals. GRAPHICAL ABSTRACT
{"title":"Crystallographic-orientation-dependent unconventional twinning pathway at the crack tip of body-centered cubic tantalum","authors":"Gaobing Wei, Hongxian Xie, G. Lu","doi":"10.1080/14786435.2023.2215549","DOIUrl":"https://doi.org/10.1080/14786435.2023.2215549","url":null,"abstract":"ABSTRACT Anti-twin has been experimentally observed in body-centered cubic nanopillars, which naturally raises the reconsideration of twinning pathways at the crack tips. Using molecular dynamics simulations, we find that shuffling anti-twinning and twinning pathways appear simultaneously at the crack tip; while only twinning pathway appears at the crack tip. By analysing the shear stress distribution of the two crack models, we reveal that the specific twinning pathway is determined by the direction relationship between the anti-twinning/twinning slip system and the butterfly-like shear stress fields. This study deepens our understanding of anti-twin and extends the knowledge about the twin formation mechanisms at the crack tips of body-centered cubic metals. GRAPHICAL ABSTRACT","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"14 5","pages":"1442 - 1452"},"PeriodicalIF":1.6,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72606757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1080/14786435.2023.2216030
M. Gayathri, P. Dhurkadevi, S. Meena, S. Ramyapriya, M. Arulmozhi
ABSTRACT Low-dimensional semiconductor systems have attracted considerable attention of the researchers because of their applications such as speed circuits, optical devices etc. The application of external perturbations like magnetic field can change the properties of these systems. Study on tilted magnetic fields is of interest theoretically as it illustrates special confinement effects. In the present study, we calculate the binding energy of a hydrogenic donor in a quantum well with a potential profile proportional to |z|2/3, called Near Triangular Quantum Well (NTQW), in the presence of a magnetic field tilted by an angle θ with the growth axis, using variational method. Calculations of hydrogenic donor binding energies are made by varying the well width (L), Aluminium composition (x), strength of the magnetic field (γ) and the tilt angle (θ). Integrated probability density (P) of finding a hydrogenic donor in NTQW is also analysed as a function of well width (L).
{"title":"Effect of tilted magnetic field on the binding energy of a hydrogenic donor in a near triangular quantum well","authors":"M. Gayathri, P. Dhurkadevi, S. Meena, S. Ramyapriya, M. Arulmozhi","doi":"10.1080/14786435.2023.2216030","DOIUrl":"https://doi.org/10.1080/14786435.2023.2216030","url":null,"abstract":"ABSTRACT Low-dimensional semiconductor systems have attracted considerable attention of the researchers because of their applications such as speed circuits, optical devices etc. The application of external perturbations like magnetic field can change the properties of these systems. Study on tilted magnetic fields is of interest theoretically as it illustrates special confinement effects. In the present study, we calculate the binding energy of a hydrogenic donor in a quantum well with a potential profile proportional to |z|2/3, called Near Triangular Quantum Well (NTQW), in the presence of a magnetic field tilted by an angle θ with the growth axis, using variational method. Calculations of hydrogenic donor binding energies are made by varying the well width (L), Aluminium composition (x), strength of the magnetic field (γ) and the tilt angle (θ). Integrated probability density (P) of finding a hydrogenic donor in NTQW is also analysed as a function of well width (L).","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"705 1","pages":"1453 - 1463"},"PeriodicalIF":1.6,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85385198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-31DOI: 10.1080/14786435.2023.2215548
Chunmei Yang, Mingwen Chen, G. Zheng, Mingli Zhang, Yan Chen, Zidong Wang
ABSTRACT The melting of micro/nanoparticles considering the Soret effect in an alloy melt is studied in terms of the asymptotic method. The results reveal that the positive Soret coefficient weakens the dynamic disequilibrium near the interface, and then enhances the melting temperature of the particle and decreases the melting speed of the particle. The negative Soret coefficient strengthens the dynamic disequilibrium near the interface, and then reduces the melting temperature of the particle and increases the melting speed of the particle. The positive Soret coefficient weakens the accumulation of the solute flux near the interface and enhances the solute concentration. The negative Soret coefficient strengthens the accumulation of the solute flux near the interface and reduces the solute concentration. The size dependence of the melting temperature considering the Soret coefficient is quantitatively consistent with the experimental data, especially for the micro/nanoparticles with a radius smaller than 5 nm.
{"title":"Melting of micro/nanoparticles in an alloy melt with the Soret effect","authors":"Chunmei Yang, Mingwen Chen, G. Zheng, Mingli Zhang, Yan Chen, Zidong Wang","doi":"10.1080/14786435.2023.2215548","DOIUrl":"https://doi.org/10.1080/14786435.2023.2215548","url":null,"abstract":"ABSTRACT The melting of micro/nanoparticles considering the Soret effect in an alloy melt is studied in terms of the asymptotic method. The results reveal that the positive Soret coefficient weakens the dynamic disequilibrium near the interface, and then enhances the melting temperature of the particle and decreases the melting speed of the particle. The negative Soret coefficient strengthens the dynamic disequilibrium near the interface, and then reduces the melting temperature of the particle and increases the melting speed of the particle. The positive Soret coefficient weakens the accumulation of the solute flux near the interface and enhances the solute concentration. The negative Soret coefficient strengthens the accumulation of the solute flux near the interface and reduces the solute concentration. The size dependence of the melting temperature considering the Soret coefficient is quantitatively consistent with the experimental data, especially for the micro/nanoparticles with a radius smaller than 5 nm.","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"63 1","pages":"1423 - 1441"},"PeriodicalIF":1.6,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83437491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-20DOI: 10.1080/14786435.2023.2208885
A. Mughal, J. Winkelmann, D. Weaire, S. Hutzler
ABSTRACT We have previously explored the hysteresis and reversibility of transitions between ordered packings of soft spheres of diameter d in cylindrical channels of diameter D [A. Mughal, J. Winkelmann, D. Weaire, S. Hutzler, Phys. Rev. E 98, 043303 (2018)]. Here we extend these initial results to include transitions between all columnar structures without inner spheres (i.e. packings in which all of the spheres are in contact with the cylindrical boundary). These results can be represented by a directed network showing permissible transitions between structures. From the hard sphere limit we deduce that there are two different types of transitions, reversible and irreversible. We explore the nature of these transitions for soft spheres as a function of pressure and due to changes in the ratio D/d. These results are illustrated by the use of schematic diagrams, indicating the topological features of each transition. Specific cases are tabulated and can be understood by reference to the appropriate schematic diagram.
{"title":"Stability maps for columnar structures","authors":"A. Mughal, J. Winkelmann, D. Weaire, S. Hutzler","doi":"10.1080/14786435.2023.2208885","DOIUrl":"https://doi.org/10.1080/14786435.2023.2208885","url":null,"abstract":"ABSTRACT We have previously explored the hysteresis and reversibility of transitions between ordered packings of soft spheres of diameter d in cylindrical channels of diameter D [A. Mughal, J. Winkelmann, D. Weaire, S. Hutzler, Phys. Rev. E 98, 043303 (2018)]. Here we extend these initial results to include transitions between all columnar structures without inner spheres (i.e. packings in which all of the spheres are in contact with the cylindrical boundary). These results can be represented by a directed network showing permissible transitions between structures. From the hard sphere limit we deduce that there are two different types of transitions, reversible and irreversible. We explore the nature of these transitions for soft spheres as a function of pressure and due to changes in the ratio D/d. These results are illustrated by the use of schematic diagrams, indicating the topological features of each transition. Specific cases are tabulated and can be understood by reference to the appropriate schematic diagram.","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"55 1","pages":"1328 - 1344"},"PeriodicalIF":1.6,"publicationDate":"2023-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87433842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-15DOI: 10.1080/14786435.2023.2212983
Iyad Alabd Alhafez, M. Kopnarski, H. Urbassek
ABSTRACT Soft layers may develop on a harder substrate during tribological processes. We perform molecular dynamics simulations of a model system, in which a hard substrate covered by a 4-nm thick soft layer is indented and scratched with a spherical tip along the surface. When scratching at a depth of only d = 2 nm – i.e. fully in the soft layer – the friction coefficient μ is the same as in a homogeneous (purely soft or hard) material; this is expected since in the ploughing regime, the friction coefficient of a sphere depends only on the indentation depth but not on the material. When scratching at d = 4 nm – i.e. at the interface between soft and hard material – μ of the bilayer material is strongly reduced compared to both the soft and the hard material. This reduction is caused by the fact that the scratching force is similar to that in a purely soft material, while the normal force is increased towards its value in the hard material. This effect also persists when scratching at d = 6 nm.
{"title":"Scratching a soft layer above a hard substrate","authors":"Iyad Alabd Alhafez, M. Kopnarski, H. Urbassek","doi":"10.1080/14786435.2023.2212983","DOIUrl":"https://doi.org/10.1080/14786435.2023.2212983","url":null,"abstract":"ABSTRACT Soft layers may develop on a harder substrate during tribological processes. We perform molecular dynamics simulations of a model system, in which a hard substrate covered by a 4-nm thick soft layer is indented and scratched with a spherical tip along the surface. When scratching at a depth of only d = 2 nm – i.e. fully in the soft layer – the friction coefficient μ is the same as in a homogeneous (purely soft or hard) material; this is expected since in the ploughing regime, the friction coefficient of a sphere depends only on the indentation depth but not on the material. When scratching at d = 4 nm – i.e. at the interface between soft and hard material – μ of the bilayer material is strongly reduced compared to both the soft and the hard material. This reduction is caused by the fact that the scratching force is similar to that in a purely soft material, while the normal force is increased towards its value in the hard material. This effect also persists when scratching at d = 6 nm.","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"23 1","pages":"1411 - 1422"},"PeriodicalIF":1.6,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78055394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-13DOI: 10.1080/14786435.2023.2209337
Nassima Guechi, B. Bennecer, S. Karfaf
ABSTRACT Phase transition, elastic, electronic, vibrational and thermal properties of (A = P and As) are investigated via performing ab-initio calculations combined with the virtual crystal approximation (VCA) and the quasi-harmonic Debye model. Our total energy results show that and undergo a phase transition from the (P4/nmm) phase to the polar LiGaGe (P ) one beyond antimony concentration of x = 0.21 and 0.36, respectively. The calculated elastic constants show that the studied alloys are mechanically stable and they also exhibit abrupt discontinuities at the transition concentrations. From Poisson's ratio and the B/G ratio, both alloys are brittle. Our results indicate that the studied alloys are semiconductors and the gap value decreases as Sb concentration increases. The calculated phonon dispersion curves for different antimony concentrations have positive frequencies. The phonon frequencies at the zone centre for the Raman-active and infrared-active modes are predicted for the and the LiGaGe structures for different antimony concentrations. The value of the polarisation is almost constant for different values of concentration. The variations of thermal expansion coefficient (α), bulk modulus (B), Debye temperature ( ), heat capacities at constant volume (C ) and the parameter (γ) as a function of pressure and temperature were all obtained and analysed in detail.
{"title":"Doping induced phase transition, elastic, electronic, vibrational and thermal properties of LiBeA1—x Sb x (A= P and As)","authors":"Nassima Guechi, B. Bennecer, S. Karfaf","doi":"10.1080/14786435.2023.2209337","DOIUrl":"https://doi.org/10.1080/14786435.2023.2209337","url":null,"abstract":"ABSTRACT Phase transition, elastic, electronic, vibrational and thermal properties of (A = P and As) are investigated via performing ab-initio calculations combined with the virtual crystal approximation (VCA) and the quasi-harmonic Debye model. Our total energy results show that and undergo a phase transition from the (P4/nmm) phase to the polar LiGaGe (P ) one beyond antimony concentration of x = 0.21 and 0.36, respectively. The calculated elastic constants show that the studied alloys are mechanically stable and they also exhibit abrupt discontinuities at the transition concentrations. From Poisson's ratio and the B/G ratio, both alloys are brittle. Our results indicate that the studied alloys are semiconductors and the gap value decreases as Sb concentration increases. The calculated phonon dispersion curves for different antimony concentrations have positive frequencies. The phonon frequencies at the zone centre for the Raman-active and infrared-active modes are predicted for the and the LiGaGe structures for different antimony concentrations. The value of the polarisation is almost constant for different values of concentration. The variations of thermal expansion coefficient (α), bulk modulus (B), Debye temperature ( ), heat capacities at constant volume (C ) and the parameter (γ) as a function of pressure and temperature were all obtained and analysed in detail.","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"1 1","pages":"1664 - 1690"},"PeriodicalIF":1.6,"publicationDate":"2023-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74863162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-11DOI: 10.1080/14786435.2023.2208884
Y. Kajikawa
ABSTRACT The experimental data of the temperature dependence of the electrical conductivity σ(T) and the Hall coefficient RH (T) on single crystal samples of n-type CdS reported in literature are reviewed and have been critically analysed including hopping conduction in an impurity band. It is shown that the experimental data of σ(T) and RH (T) reported in almost previous studies can be simultaneously fitted using a common set of the values of material parameters for calculating free-electron conduction, i.e. the conduction and the density-of-state effective mass of electrons, the acoustic-phonon deformation potential, the Fröhlich coupling constant and the piezoelectric coupling coefficient, whereas wide ranges of values for these material parameters had been adopted in different studies. The correct assignment of impurity conduction mechanisms in n-type CdS single crystals is presented. In addition, reasonable explanations are given for unresolved enigmas regarding impurity pairing, unexpected large Hall mobility at low temperatures, and the effect of electric field on hopping Hall mobility.
{"title":"Electrical conductivity and Hall effect in n-type CdS","authors":"Y. Kajikawa","doi":"10.1080/14786435.2023.2208884","DOIUrl":"https://doi.org/10.1080/14786435.2023.2208884","url":null,"abstract":"ABSTRACT The experimental data of the temperature dependence of the electrical conductivity σ(T) and the Hall coefficient RH (T) on single crystal samples of n-type CdS reported in literature are reviewed and have been critically analysed including hopping conduction in an impurity band. It is shown that the experimental data of σ(T) and RH (T) reported in almost previous studies can be simultaneously fitted using a common set of the values of material parameters for calculating free-electron conduction, i.e. the conduction and the density-of-state effective mass of electrons, the acoustic-phonon deformation potential, the Fröhlich coupling constant and the piezoelectric coupling coefficient, whereas wide ranges of values for these material parameters had been adopted in different studies. The correct assignment of impurity conduction mechanisms in n-type CdS single crystals is presented. In addition, reasonable explanations are given for unresolved enigmas regarding impurity pairing, unexpected large Hall mobility at low temperatures, and the effect of electric field on hopping Hall mobility.","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"72 1","pages":"1464 - 1506"},"PeriodicalIF":1.6,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85910136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.1080/14786435.2023.2203525
Yunji Shi, Rundong Wan, Zheng-gang Zhang, Ying Lei, G. Tian
ABSTRACT Half-Heusler compounds have excellent power generation performance at high temperatures. The scattering mechanism is an essential factor affecting the electrical transport properties of thermoelectric materials. In computational simulations, only the role of acoustic phonon scattering on the thermoelectric properties of materials is considered, whereas other scattering mechanisms are neglected. In this work, we investigate the thermoelectric properties of NbCoGe compounds with different combinations of acoustic deformation potential, polar optical phonon, and ionised impurity scattering mechanisms. The calculated results show that the ZT values of n-type and p-type NbCoGe compounds reach 8 and 2.8, respectively, when only acoustic deformation potential scattering is considered, indicating that this sole scattering is insufficient. The calculated ZT values of p-type NbCoGe compounds reach 1.8 at 1200 K and more than 1 at 800 K for p- and n-type NbCoGe compounds under the combined effect of the three scattering mechanisms due to their high–power factor. This provides solid theoretical guidance for the search for potentially high–temperature half-Heusler thermoelectric materials.
{"title":"First-principles research on the thermoelectric properties of NbCoGe based on the scattering mechanisms","authors":"Yunji Shi, Rundong Wan, Zheng-gang Zhang, Ying Lei, G. Tian","doi":"10.1080/14786435.2023.2203525","DOIUrl":"https://doi.org/10.1080/14786435.2023.2203525","url":null,"abstract":"ABSTRACT Half-Heusler compounds have excellent power generation performance at high temperatures. The scattering mechanism is an essential factor affecting the electrical transport properties of thermoelectric materials. In computational simulations, only the role of acoustic phonon scattering on the thermoelectric properties of materials is considered, whereas other scattering mechanisms are neglected. In this work, we investigate the thermoelectric properties of NbCoGe compounds with different combinations of acoustic deformation potential, polar optical phonon, and ionised impurity scattering mechanisms. The calculated results show that the ZT values of n-type and p-type NbCoGe compounds reach 8 and 2.8, respectively, when only acoustic deformation potential scattering is considered, indicating that this sole scattering is insufficient. The calculated ZT values of p-type NbCoGe compounds reach 1.8 at 1200 K and more than 1 at 800 K for p- and n-type NbCoGe compounds under the combined effect of the three scattering mechanisms due to their high–power factor. This provides solid theoretical guidance for the search for potentially high–temperature half-Heusler thermoelectric materials.","PeriodicalId":19856,"journal":{"name":"Philosophical Magazine","volume":"80 1","pages":"1396 - 1410"},"PeriodicalIF":1.6,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78151239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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