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Twisted Yangian Y(sp_(2))的单权模 被引量:1
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作者 刘晓华 谭易兰 夏利猛 《东北师大学报(自然科学版)》 CAS 北大核心 2024年第1期1-7,共7页
讨论了Twisted Yangian Y(sp_(N))的权模问题,构造了Y(sp_(2))的一类无限维单权模,分类了具有一个一维权空间的Y(sp_(2))单权模.
关键词 twisted Yangian 权模 单模 Dense模 Pointed模
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Valley-dependent transport in a mescoscopic twisted bilayer graphene device
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作者 史文萱 刘翰林 汪军 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期61-65,共5页
We study the valley-dependent electron transport in a four-terminal mesoscopic device of the two monolayer graphene nanoribbons vertically stacked together, where the intersection forms a bilayer graphene lattice with... We study the valley-dependent electron transport in a four-terminal mesoscopic device of the two monolayer graphene nanoribbons vertically stacked together, where the intersection forms a bilayer graphene lattice with a controllable twist angle. Using a tight-binding lattice model, we show that the longitudinal and transverse conductances exhibit significant valley polarization in the low energy regime for small twist angles. As the twist angle increases, the valley polarization shifts to the high energy regime. This arises from the regrouping effect of the electron band in the twisted bilayer graphene region. But for relatively large twist angles, no significant valley polarization is observed. These results are consistent with the spectral densities of the twisted bilayer graphene. 展开更多
关键词 twisted bilayer graphene valley-dependent transport graphene nanoribbon CONDUCTANCE
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Wafer-scale 30°twisted bilayer graphene epitaxially grown on Cu_(0.75)Ni_(0.25)(111)
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作者 马鹏程 张翱 +10 位作者 甄洪润 江志诚 杨逸尘 丁建阳 刘正太 刘吉山 沈大伟 于庆凯 刘丰 张学富 刘中灏 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期467-471,共5页
Twisted bilayer graphene(TBG) has been extensively studied because of its novel physical properties and potential application in electronic devices.Here we report the synthesis and characterization of 300 TBG naturall... Twisted bilayer graphene(TBG) has been extensively studied because of its novel physical properties and potential application in electronic devices.Here we report the synthesis and characterization of 300 TBG naturally grown on Cu_(0.75)Ni_(0.25)(111) film and investigate the electronic structure by angle-resolved photoemission spectroscopy.Compared with other substrates,our TBG with a wafer scale is acquired with a shorter growth time.The Fermi velocity and energy gap of Dirac cones of TBG are comparable with those of a monolayer on Cu_(0.85)Ni_(0.15)(111).The signature of moré lattices has not been observed in either the low-energy electron diffraction patterns or the Fermi surface map within experimental resolution,possibly due to different Cu and Ni contents in the substrates enhancing the different couplings between the substrate and the first/second layers and hindering the formation of a quasiperiodic structure. 展开更多
关键词 twisted bilayer graphene electronic structure Cu/Ni(111)
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Twisted Yangian Y(sp^(2))的一类单权模
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作者 周义坤 谭易兰 徐森荣 《东北师大学报(自然科学版)》 CAS 北大核心 2024年第3期1-4,共4页
研究了Twisted Yangian Y(g_(N))的权模问题,构造了Y(sp^(2))的一类权空间维数均为2的无限维权模,给出了该权模不可约的充分条件.
关键词 twisted Yangian 权模 单模
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Tubular Heat Enhancement Using Twisted Tape Inserts with Large Holes
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作者 Ali Jaber Abdulhamed Aws Al-Akam +1 位作者 Wisam J.Khudhayer Ali Sabri Allw 《Energy Engineering》 EI 2024年第2期273-290,共18页
Heat augmentation techniques play a vital role in the heating and cooling processes in industries,including solar collectors and many applications that utilize heat exchangers.Several studies are based on inserting fi... Heat augmentation techniques play a vital role in the heating and cooling processes in industries,including solar collectors and many applications that utilize heat exchangers.Several studies are based on inserting fillers inside the tubes to enhance heat transfer.This investigation considered the effects of twisted tapes with large holes on a tubular heat exchanger’s(HX)heat transmission,pressure drop,and thermal boosting factor.In the experimental section,counter-swirl flow generators used twisted tapes with pairs of 1.0 cm-diameter holes and changes in porosity(Rp)at 1.30%and 2.70%.In the experiments,air was utilized as a working fluid in a tube with a circular cross-section.The turbulent flow was considered,with Reynolds numbers(Re)domain from 4800 to 9500,and a boundary condition with a uniform wall heat flux was constructed.The findings expound that when the number of holes rose,the Nusselt number(Nu),the factor of friction(f),and the thermal enhancement factor(η)all increased as well.Additionally,as the friction factor increased,the Nusselt number of the tape-equipped tube was noticeably higher.Additionally,it was discovered that the friction factor was between 70%and 94%lower than the values of the tube without tape,while the(Nu)was between 87%and 97%higher than the conventional tube values.The maximum value ofηis 89%.According to the experimental results,empirical correlations for Nu,f,andηwere also generated. 展开更多
关键词 TUBULAR heat exchanger tape inserts twisted tape
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Linear Functional Equations and Twisted Polynomials
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作者 Moumouni Djassibo Woba 《Journal of Applied Mathematics and Physics》 2024年第4期1459-1471,共13页
A certain variety of non-switched polynomials provides a uni-figure representation for a wide range of linear functional equations. This is properly adapted for the calculations. We reinterpret from this point of view... A certain variety of non-switched polynomials provides a uni-figure representation for a wide range of linear functional equations. This is properly adapted for the calculations. We reinterpret from this point of view a number of algorithms. 展开更多
关键词 Functional Equations twisted Polynomials RINGS MORPHISMS Euclidian Division
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Twisted Integration of Complex Oxide Magnetoelectric Heterostructures via Water‑Etching and Transfer Process
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作者 Guannan Yang Guohua Dong +4 位作者 Butong Zhang Xu Xu Yanan Zhao Zhongqiang Hu Ming Liu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第1期360-369,共10页
Manipulating strain mode and degree that can be applied to epitaxial complex oxide thin films have been a cornerstone of strain engineering.In recent years,lift-off and transfer technology of the epitaxial oxide thin ... Manipulating strain mode and degree that can be applied to epitaxial complex oxide thin films have been a cornerstone of strain engineering.In recent years,lift-off and transfer technology of the epitaxial oxide thin films have been developed that enabled the integration of heterostructures without the limitation of material types and crystal orientations.Moreover,twisted integration would provide a more interesting strategy in artificial magnetoelectric heterostructures.A specific twist angle between the ferroelectric and ferromagnetic oxide layers corresponds to the distinct strain regulation modes in the magnetoelectric coupling process,which could provide some insight in to the physical phenomena.In this work,the La_(0.67)Sr_(0.33)MnO_(3)(001)/0.7Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.3PbTiO_(3)(011)(LSMO/PMN-PT)heterostructures with 45.and 0.twist angles were assembled via water-etching and transfer process.The transferred LSMO films exhibit a fourfold magnetic anisotropy with easy axis along LSMO<110>.A coexistence of uniaxial and fourfold magnetic anisotropy with LSMO[110]easy axis is observed for the 45°Sample by applying a 7.2 kV cm^(−1)electrical field,significantly different from a uniaxial anisotropy with LSMO[100]easy axis for the 0°Sample.The fitting of the ferromagnetic resonance field reveals that the strain coupling generated by the 45°twist angle causes different lattice distortion of LSMO,thereby enhancing both the fourfold and uniaxial anisotropy.This work confirms the twisting degrees of freedom for magnetoelectric coupling and opens opportunities for fabricating artificial magnetoelectric heterostructures. 展开更多
关键词 Magnetoelectric heterostructures Twist angle Epitaxial lift-off Magnetic anisotropy Ferromagnetic resonance
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Visualizing the Local Twist Angle Variation within and between Domains of Twisted Bilayer Graphene
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作者 户佳玮 朱诗雨 +7 位作者 胡倩颖 王云昊 申承民 杨海涛 竺晓山 郇庆 许杨 高鸿钧 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第3期146-151,共6页
Moirésuperlattices in twisted two-dimensional materials have emerged as ideal platforms for engineering quantum phenomena,which are highly sensitive to twist angles,including both the global value and the spatial... Moirésuperlattices in twisted two-dimensional materials have emerged as ideal platforms for engineering quantum phenomena,which are highly sensitive to twist angles,including both the global value and the spatial inhomogeneity.However,only a few methods provide spatial-resolved information for characterizing local twist angle distribution. 展开更多
关键词 ANGLE TWIST TWIST
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Preface to Special Topic on Twisted van der Waals Heterostructures 被引量:1
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作者 Jun Zhang Zhongming Wei 《Journal of Semiconductors》 EI CAS CSCD 2023年第1期1-2,共2页
Twisted van der Waals heterostructures are becoming the building blocks for engineering new device structures, in which their electronic, optical and mechanical properties can be tuned by changing the “twist” angle ... Twisted van der Waals heterostructures are becoming the building blocks for engineering new device structures, in which their electronic, optical and mechanical properties can be tuned by changing the “twist” angle between layers of 2D materials. Such twisted 2D heterostructures offer a unique opportunity to create a new field of “twistronics” by mechanically stacking different 2D van der Waals materials together. 展开更多
关键词 materials TWIST twisted
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Natural vibration of cantilever porous twisted plate with variable thickness in different directions
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作者 Y.X.Hao Y.Y.Liu +3 位作者 W.Zhang L.T.Liu K.C.Sun S.W.Yang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第9期200-216,共17页
In this paper,the blade is assumed to be a rotating variable thickness cantilever twisted plate structure,and the natural vibrations of variable thickness cantilever twisted plate made of metal porous material are stu... In this paper,the blade is assumed to be a rotating variable thickness cantilever twisted plate structure,and the natural vibrations of variable thickness cantilever twisted plate made of metal porous material are studied.It is assumed that the thickness of the plate changes along spanwise direction and chordwise direction,respectively,and it changes in both directions.The classical thin shell theory,the first and second fundamental forms of surface and von Karman geometric relationship are employed to derive the total potential energy and kinetic energy of the cantilever twisted plate,in which the centrifugal force potential due to high rotational speed is included.Then,according to the Rayleigh-Ritz procedure and applying the polynomial functions which satisfy the cantilever boundary conditions,the dynamic system expressed by equations of motion is reduced to an eigenvalue problem.By numerical simulation,the frequency curves and the mode shapes of the twisted plate can be obtained to reveal the internal connection between natural vibration and the parameters.A series of comparison studies are performed to verify the accuracy of the present formulation and calculations,in which compared data come from experimental,finite element method and theoretical calculation,respectively.The influence of pre-twist angle,three different forms of thickness taper ratio and rotational speed on natural vibration,mode exchange and frequency veering phenomenon of the system is discussed in detail.In addition,the approach proposed here can efficiently extract analytical expressions of mode functions for rotating variable thickness cantilever twisted plate structures. 展开更多
关键词 Porous cantilever twisted plate Variable thickness Natural vibration Frequency veering Mode exchange
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Correlated states in alternating twisted bilayer–monolayer–monolayer graphene heterostructure
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作者 牛锐锐 韩香岩 +5 位作者 曲壮壮 王知雨 李卓贤 刘倩伶 韩春蕊 路建明 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第1期94-99,共6页
Highly controlled electronic correlation in twisted graphene heterostructures has gained enormous research interests recently,encouraging exploration in a wide range of moirésuperlattices beyond the celebrated tw... Highly controlled electronic correlation in twisted graphene heterostructures has gained enormous research interests recently,encouraging exploration in a wide range of moirésuperlattices beyond the celebrated twisted bilayer graphene.Here we characterize correlated states in an alternating twisted Bernal bilayer–monolayer–monolayer graphene of~1.74°,and find that both van Hove singularities and multiple correlated states are asymmetrically tuned by displacement fields.In particular,when one electron per moiréunit cell is occupied in the electron-side flat band,or the hole-side flat band(i.e.,three holes per moiréunit cell),the correlated peaks are found to counterintuitively grow with heating and maximize around 20 K–a signature of Pomeranchuk effect.Our multilayer heterostructure opens more opportunities to engineer complicated systems for investigating correlated phenomena. 展开更多
关键词 twisted graphene heterostructure Pomeranchuk effect correlated states van Hove singularity
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Machine learning of theΓ-point gap and flat bands of twisted bilayer graphene at arbitrary angles
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作者 马宵怡 罗宇峰 +4 位作者 李梦可 焦文艳 袁红梅 刘惠军 方颖 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第5期32-36,共5页
The novel electronic properties of bilayer graphene can be fine-tuned via twisting,which may induce flat bands around the Fermi level with nontrivial topology.In general,the band structure of such twisted bilayer grap... The novel electronic properties of bilayer graphene can be fine-tuned via twisting,which may induce flat bands around the Fermi level with nontrivial topology.In general,the band structure of such twisted bilayer graphene(TBG)can be theoretically obtained by using first-principles calculations,tight-binding method,or continuum model,which are either computationally demanding or parameters dependent.In this work,by using the sure independence screening sparsifying operator method,we propose a physically interpretable three-dimensional(3D)descriptor which can be utilized to readily obtain theΓ-point gap of TBG at arbitrary twist angles and different interlayer spacings.The strong predictive power of the descriptor is demonstrated by a high Pearson coefficient of 99%for both the training and testing data.To go further,we adopt the neural network algorithm to accurately probe the flat bands of TBG at various twist angles,which can accelerate the study of strong correlation physics associated with such a fundamental characteristic,especially for those systems with a larger number of atoms in the unit cell. 展开更多
关键词 twisted bilayer graphene band gap flat bands machine learning
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Straight and twisted Weyl nodal line phonons in Ho2CF2 material
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作者 康鑫越 李金洋 李思 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第11期77-81,共5页
Based on first-principles calculations, symmetry analysis and model construction, we predict that Ho2CF2hosts both straight and twisted Weyl nodal lines in its bulk phonon spectrum. We identify that the top two phonon... Based on first-principles calculations, symmetry analysis and model construction, we predict that Ho2CF2hosts both straight and twisted Weyl nodal lines in its bulk phonon spectrum. We identify that the top two phonon bands entangle with each other, forming two straight Weyl nodal lines on the K–H and K′–H′paths at the Brillouin zone(BZ) boundary,and six twisted Weyl nodal lines within the BZ. All the Weyl nodal lines along the kz direction and across the entire BZ.The symmetry analysis indicates that these Weyl nodal lines are protected by the PT symmetry and crystal symmetry. The Berry phase and drumhead-like nontrivial surface states are calculated. We also construct a tight-binding model to describe these nodal lines. Our work provides an excellent material platform for exploring the fascinating physics associated with straight and twisted Weyl nodal line phonons. 展开更多
关键词 topological quasiparticles topological phonons straight nodal lines twisted nodal lines
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Optical Tunable MoiréExcitons in Twisted Hexagonal GaTe Bilayers
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作者 韩锦森 赖康 +3 位作者 余晓翔 陈家浩 郭宏礼 戴佳钰 《Chinese Physics Letters》 SCIE EI CAS CSCD 2023年第6期86-91,共6页
Optical fine-tunable layer-hybridized Moiréexcitons are highly in demand for emerging many-body states in two-dimensional semiconductors.We report naturally confined layer-hybridized bright Moiréexcitons wit... Optical fine-tunable layer-hybridized Moiréexcitons are highly in demand for emerging many-body states in two-dimensional semiconductors.We report naturally confined layer-hybridized bright Moiréexcitons with long lifetimes in twisted hexagonal GaTe bilayers,using ab initio many-body perturbation theory and the Bethe–Salpeter equation.Due to the hybridization of electrons and holes between layers,which enhances the brightness of excitons,the twisted bilayer system becomes attractive for optical applications.We find that in both R and H-type stacking Moirésuperlattices,more than 200 meV lateral quantum confinements occur on exciton energies,which results in two scenarios:(1)The ground state bright excitons XA are found to be trapped at two high-symmetry points,with opposite electric dipoles in the R-stacking Moirésupercell,forming a honeycomb superlattice of nearest-neighbor dipolar attraction.(2)For H-stacking case,the XA is found to be trapped at only one high-symmetry point exhibiting a triangular superlattice.Our results suggest that twisted h-GaTe bilayer is one of the promising systems for optical fine-tunable excitonic devices and provide an ideal platform for realizing strong correlated Bose–Hubbard physics. 展开更多
关键词 equation twisted STACKING
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Coupled Ferroelectricity and Correlated States in a Twisted Quadrilayer MoS_(2) Moiré Superlattice
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作者 吴帆帆 李璐 +12 位作者 徐巧玲 刘乐 袁亚龙 赵交交 黄智恒 昝晓洲 Kenji Watanabe Takashi Taniguchi 时东霞 冼乐德 杨威 杜罗军 张广宇 《Chinese Physics Letters》 SCIE EI CAS CSCD 2023年第4期68-73,共6页
Moiré superlattices have emerged as a highly controllable quantum platform for exploration of various fascinating phenomena,such as Mott insulator states,ferroelectric order,unconventional superconductivity and o... Moiré superlattices have emerged as a highly controllable quantum platform for exploration of various fascinating phenomena,such as Mott insulator states,ferroelectric order,unconventional superconductivity and orbital ferromagnetism.Although remarkable progress has been achieved,current research in moiré physics has mainly focused on the single species properties,while the coupling between distinct moiré quantum phenomena remains elusive.Here we demonstrate,for the first time,the strong coupling between ferroelectricity and correlated states in a twisted quadrilayer MoS2moiré superlattice,where the twist angles are controlled in sequence to be ~57°,~0°,and ~-57°.Correlated insulator states are unambiguously established at moiré band filling factors v = 1,2,3 of twisted quadrilayer MoS_(2).Remarkably,ferroelectric order can occur at correlated insulator states and disappears quickly as the moiré band filling deviates from the integer fillings,providing smoking gun evidences of the coupling between ferroelectricity and correlated states.Our results demonstrate the coupling between different moiré quantum properties and will hold great promise for new moiré physics and applications. 展开更多
关键词 FERROELECTRIC quantum twisted
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Emergence of correlations in twisted monolayer-trilayer graphene heterostructures
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作者 周璋 Kenji Watanabe +3 位作者 Takashi Taniguchi 林晓 毛金海 高鸿钧 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第9期74-78,共5页
Twisted bilayer graphene heterostructures have recently emerged as a well-established platform for studying strongly correlated phases,such as correlated insulating,superconducting,and topological states.Extending thi... Twisted bilayer graphene heterostructures have recently emerged as a well-established platform for studying strongly correlated phases,such as correlated insulating,superconducting,and topological states.Extending this notion to twisted multilayer graphene heterostructures has exhibited more diverse correlated phases,as some fundamental properties related to symmetry and band structures are correspondingly modified.Here,we report the observations of correlated states in twisted monolayer-trilayer(Bernal stacked)graphene heterostructures.Correlated phases at integer fillings of the moire unit cell are revealed at a high displacement field and stabilized with a moderate magnetic field on the electron-doping side at a twist angle of 1.45°,where the lift of degeneracy at the integer fillings is observed in the Landau fan diagram.Our results demonstrate the effectiveness of moire engineering in an extended structure and provide insights into electric-field tunable correlated phases. 展开更多
关键词 twisted multilayer graphene correlated states electric tuning
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Tunable correlation in twisted monolayer–trilayer graphene
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作者 丁冬冬 牛锐锐 +6 位作者 韩香岩 曲壮壮 王知雨 李卓贤 刘倩伶 韩春蕊 路建明 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期96-101,共6页
Flat-band physics of moirésuperlattices,originally discovered in the celebrated twisted bilayer graphene,have recently been intensively explored in multilayer graphene systems that can be further controlled by el... Flat-band physics of moirésuperlattices,originally discovered in the celebrated twisted bilayer graphene,have recently been intensively explored in multilayer graphene systems that can be further controlled by electric field.In this work,we experimentally find the evidence of correlated insulators at half filling of the electron moiréband of twisted monolayer–trilayer graphene with a twist angle around 1.2°.Van Hove singularity(VHS),manifested as enhanced resistance and zero Hall voltage,is observed to be distinct in conduction and valence flat bands.It also depends on the direction and magnitude of the displacement fields,consistent with the asymmetric crystal structure.While the resistance ridges at VHS can be enhanced by magnetic fields,when they cross commensurate fillings of the moirésuperlattice in the conduction band,the enhancement is so strong that signatures of correlated insulator appear,which may further develop into an energy gap depending on the correlation strength.At last,Fermi velocity derived from temperature coefficients of resistivity is compared between conduction and valence bands with different displacement fields.It is found that electronic correlation has a negative dependence on the Fermi velocity,which in turn could be used to quantify the correlation strength. 展开更多
关键词 twisted multilayer graphene heterostructure correlated states van Hove singularity
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Pipes with Trapezoidal Cut Twisted Tape Inserts in the Laminar Flow Regime:Nusselt Number and Friction Coefficient Analysis
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作者 Shrikant Arunrao Thote Netra Pal Singh 《Fluid Dynamics & Materials Processing》 EI 2023年第2期501-511,共11页
The thermal behavior of pipes with a twisted tape inside(used to enhance heat transfer through the tube wall)is studied in the laminar flow regime.Oil is used as the work fluid with the corresponding Reynolds Number s... The thermal behavior of pipes with a twisted tape inside(used to enhance heat transfer through the tube wall)is studied in the laminar flow regime.Oil is used as the work fluid with the corresponding Reynolds Number spanning the interval 200–2000.It is found that in such conditions the‘Nusselt Number’(Nu)gradually increases with reducing the tape twist ratio,whereas the friction factor is detrimentally affected by the presence of the tape(as witnessed by the comparison with the companion case where a plain tube is considered).In particular,it is shown that the heat transfer efficiency can be improved by nearly 69%if tape inserts with a relatively low twist ratio are used.On the basis of these findings,it is concluded that loose fit tape inserts are superior to tight fit tapes in terms of heat transfer and ease of replacement. 展开更多
关键词 Friction factor laminar flow Nusselt Number trapezoidal-cut twisted tape
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Analysis of Friction and Heat Transfer Characteristics of Tubes with Trapezoidal Cut Twisted Tape Inserts
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作者 Shrikant Arunrao Thote Netra Pal Singh 《Fluid Dynamics & Materials Processing》 EI 2023年第3期711-722,共12页
The thermo-hydraulic properties of circular tubes with a twisted tape inside(used accordingly to induce turbulence and enhance heat transfer through the tube wall)are described for Reynolds Numbers ranging from 830 to... The thermo-hydraulic properties of circular tubes with a twisted tape inside(used accordingly to induce turbulence and enhance heat transfer through the tube wall)are described for Reynolds Numbers ranging from 830 to 1990.Tapes twisted with the three distinct twist ratios are considered,namely,6,4.4 and 3.Air is used as the working fluid in several tests.For the sake of comparison,the standard tube with no insert is also examined.It is shown that in the presence of the twisted tape,the‘frictional factor’,‘Nusselt Number’and the‘thermal performance factor’are much higher than those obtained for the plain tube.Moreover,the tapes having the lowest twist ratio,i.e.,3,are more effective than the others in terms of heat transfer augmentation.The‘thermal performance factor’is greater than one for all the twisted tapes used in the experiments,which confirms the enhanced performances of the heat exchanger and the related savings in terms of total energy. 展开更多
关键词 Friction factor nusselt number performance ratio trapezoidal cut twisted tape insert
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Large valley Nernst effect in twisted multilayer graphene systems
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作者 简冠林 朱振刚 苏刚 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第10期22-30,共9页
Valley Nernst effect is a newly proposed and experimentally confirmed effect,which could be used to design novel thermoelectric devices.We study the valley Nernst effect in(M+N)-layer twisted multilayer graphene syste... Valley Nernst effect is a newly proposed and experimentally confirmed effect,which could be used to design novel thermoelectric devices.We study the valley Nernst effect in(M+N)-layer twisted multilayer graphene systems by a simple low-energy effective model.It is found that the total valley Nernst coefficient(VNC)is three orders of magnitude larger than that in monolayer group-Ⅵdichalcogenides.The total VNC increases with the increase of layer numbers.It is shown that the total VNC exhibits a structure with three peaks as a function of the Fermi energy.We identify that the central peak is always negative stemming from the flat band.Two shoulder peaks are positively induced by the conduction and valence bands,respectively.These predicted features can be tested experimentally.The present work would shed more light on valley caloritronics. 展开更多
关键词 valley Nernst effect twisted multilayer graphene
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