The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mechanisms of regulating thermal transport properties plays a key role....The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mechanisms of regulating thermal transport properties plays a key role.Herein,we elaborately investigate the effect of vertical(out-of-plane)piezoelectric characteristics on thermal transport,which is historically undiscovered.The different stacking-order(AA and AB)bilayer boron nitride(Bi-BN)in two-dimensional(2D)materials are selected as study cases.By performing state-of-the-art first-principles calculations,it is found that the polarization charge along the out-of-plane orientation ascends significantly with the increasing piezoelectric response in AB stacked Bi-BN(Bi-BN-AB)followed by the enhanced interlayer B–N atomic interactions.Consequently,the amplitude of phonon anharmonicity in Bi-BN-AB increases larger than that in the AA stacked Bi-BN(Bi-BN-AA),resulting in the dramatic weakening of the thermal conductivity by 20.34%under 18%strain.Our research reveals the significant role of the vertical(out-of-plane)piezoelectric characteristic in regulating thermal transport and provides new insight into accurately exploring the thermal transport performance of 2D van der Waals materials.展开更多
The design of novel devices with specific technical interests through modulating structural properties and bonding characteristics promotes the vigorous development of materials informatics.Boron arsenide and boron ni...The design of novel devices with specific technical interests through modulating structural properties and bonding characteristics promotes the vigorous development of materials informatics.Boron arsenide and boron nitride,as remarkably high thermal conductivity(κ)materials,are unfavorable for thermal insulation applications as well as thermoelectric devices.In this study,based on first-principles calculations,we identify a group of novel borides with ultra-lowκ,i.e.,g-B_(3)X_(5)(X=N,P,and As).Theκof g-B_(3)N_(5),g-B_(3)P_(5),and g-B_(3)As_(5)are 21.08,2.50,and 1.85 W·m^(-1)·K^(-1),respectively,which are boron nitride and boron arsenide systems with the lowestκreported so far.The ultra-lowκis attributed to the synergy effect of electronics(lone-pair electrons)and geometry(buckling structures)on thermal transport.The discovery of the ultralowκof boron nitride and boron arsenide systems can well fill the gaps in applications of thermal insulation and thermoelectric devices.展开更多
基金This study was financially supported by the National Natural Science Foundation of China(Nos.52006057,51906097 and 11904324)the Fundamental Research Funds for the Central Universities(Nos.531119200237 and 541109010001)the State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body at Hunan University(No.52175013).
文摘The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mechanisms of regulating thermal transport properties plays a key role.Herein,we elaborately investigate the effect of vertical(out-of-plane)piezoelectric characteristics on thermal transport,which is historically undiscovered.The different stacking-order(AA and AB)bilayer boron nitride(Bi-BN)in two-dimensional(2D)materials are selected as study cases.By performing state-of-the-art first-principles calculations,it is found that the polarization charge along the out-of-plane orientation ascends significantly with the increasing piezoelectric response in AB stacked Bi-BN(Bi-BN-AB)followed by the enhanced interlayer B–N atomic interactions.Consequently,the amplitude of phonon anharmonicity in Bi-BN-AB increases larger than that in the AA stacked Bi-BN(Bi-BN-AA),resulting in the dramatic weakening of the thermal conductivity by 20.34%under 18%strain.Our research reveals the significant role of the vertical(out-of-plane)piezoelectric characteristic in regulating thermal transport and provides new insight into accurately exploring the thermal transport performance of 2D van der Waals materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52006057,52006059 and 51906097)the Fundamental Research Funds for the Central Universities(Nos.531119200237 and 541109010001531118010490)+1 种基金the State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body at Hunan University(No.52175011)RWTH Aachen University under project bund0011。
文摘The design of novel devices with specific technical interests through modulating structural properties and bonding characteristics promotes the vigorous development of materials informatics.Boron arsenide and boron nitride,as remarkably high thermal conductivity(κ)materials,are unfavorable for thermal insulation applications as well as thermoelectric devices.In this study,based on first-principles calculations,we identify a group of novel borides with ultra-lowκ,i.e.,g-B_(3)X_(5)(X=N,P,and As).Theκof g-B_(3)N_(5),g-B_(3)P_(5),and g-B_(3)As_(5)are 21.08,2.50,and 1.85 W·m^(-1)·K^(-1),respectively,which are boron nitride and boron arsenide systems with the lowestκreported so far.The ultra-lowκis attributed to the synergy effect of electronics(lone-pair electrons)and geometry(buckling structures)on thermal transport.The discovery of the ultralowκof boron nitride and boron arsenide systems can well fill the gaps in applications of thermal insulation and thermoelectric devices.
