人工分子磁体中的温差电效应
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摘要
文章研究人工分子磁体中的塞贝克效应,发现人工分子磁体可以产生温差电流,且其铁磁态和反铁磁态的竞争导致正向电流和反向电流的叠加或抵消,进而产生非线性电流效应。温差电流随分子轨道能级变化展现出台阶现象。塞贝克系数在双通道时表现为反对称结构。这些结果源于正向、反向电流的竞争。
We study the Seebeck effect in an artificial single molecular magnet(ASMM)junction.It is found that the ASMM connected with electrodes can generate temperature-induced current,and the current are affected by ASMM's ferromagnetic states and anti-ferromagnetic states.There are forward current when the states are above the Fermi surface and backward current when the states are below the Fermi surface.The competition of forward current and backward current induces rich nonlinear current behaviors.
We study the Seebeck effect in an artificial single molecular magnet(ASMM)junction.It is found that the ASMM connected with electrodes can generate temperature-induced current,and the current are affected by ASMM's ferromagnetic states and anti-ferromagnetic states.There are forward current when the states are above the Fermi surface and backward current when the states are below the Fermi surface.The competition of forward current and backward current induces rich nonlinear current behaviors.
引文
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[2] Dubi Y,Ventra M D.Heat Flow and Thermoelectricity in Atomic and Molecular Junctions[J].Rev Mod Phys,2011,83:131155.DOI:10.1103/RevModPhys.83.131.
[3] Pulizzi F.Heat at the Borders[J].Nature Materials,2011,10:724-1.DOI:10.1038/nmat3136.
[4] Van Herwaarden A W,Sarro P M.Thermal Sensors Based on the Seebeck Effect[J].Sensors and Actuators,1986,10:321-346.DOI:10.1016/0250-6874(86)80053-1.
[5] Uchida K I,Adachi H,Ota T,et al.Observation of Longitudinal Spin-Seebeck Effect in Magnetic Insulators[J].Appl Phys Lett,2010,97:172505-3.DOI:10.1063/1.3507386.
[6] Ramos-Andrade J P,Pena F J,Gonzalez A,et al.Spin-Seebeck Effect and Spin Polarization in a Multiple Quantum Dot Molecule[J].Phys Rev B,2017,96:165413-10.DOI:10.1103/PhysRevB.96.165413.
[7] Zhang Z,Jiang L,Wang R Q,et al.Thermoelectric Induced Spin Currents in Single-Molecule Magnet Tunnel Junction[J].Appl Phys Lett,2010,97:242101-3.DOI:10.1063/1.3525571.
[8] Wang R Q,Sheng L,Shen R,et al.Thermoelectric Effect in Single Molecule Magnet Junctions[J].Phys Rev Lett,2010,105:057202-4.DOI:10.1103/PhysRevLett.105.057202.
[9] Niu P B,Liu L X,Su X Q,et al.Spin Seebeck Effect in a Metal-Single-Molecule-Magnet-Metal Junction[J].AIP Advances,2018,8:015215-6.DOI:10.1063/1.5005131.
[10] Niu P B,Shi Y L,Sun Z,et al.Thermoelectric ZT Enhanced by Asymmetric Configuration in Single-Molecule-Magnet Junctions[J].J Phys D:Appl Phys,2016,49:045002-6.DOI:10.1088/0022-3727/49/4/045002.
[11] Contreras-Pulido L D.Aguado R Shot Noise Spectrum of Artificial Single Molecule Magnets:Measuring Spin Relaxation Times via the Dicke Effect[J].Phys Rev B,2010,81:161309-5.DOI:10.1103/PhysRevB.81.161309.
[12] Besombes L,Leger Y,Maingault L,et al.Probing the Spin State of a Single Magnetic Ion in an Individual Quantum Dot[J].Phys Rev Lett1,2004,93:207403-4.DOI:10.1103/PhysRevLett.93.207403.
[13] Leger Y,Besombes L,Maingault L,et al.Geometrical Effects on the Optical Properties of Quantum Dots Doped with a Single Magnetic Atom[J].Phys Status Solidi C,2005,95:047403-5.DOI:10.1103/PhysRevLett.95.047403.
[14] Fernandez-Rossier J,Aguado R.Mn-dopedⅡ-ⅥQuantum Dots:Artificial Molecular Magnets[J].Phys Status Solidi C,2006,3:37343739.DOI:10.1002/pssc.200671504.
[15] Kostyrko T,Bulka B R.Hubbard Operators Approach to the Transport in Molecular Junctions[J].Phys Rev B,2005,71:235306-10.DOI:10.1103/PhysRevB.71.235306.
[16] Niu P B,Zhang Y Y,Wang Q,et al.Quantum Transport through Anisotropic Molecular Magnets:Hubbard Green Function Approach[J].Phys Lett A,2012,376:1481-1488.DOI:10.1016/j.physleta.2012.03.007.
[17] Meir Y,Wingreen N S.Landauer Formula for the Current through an Interacting Electron Region[J].Phys Rev Lett,1992,68:2512-2515.DOI:10.1103/PhysRevLett.68.2512.
[18] Haug H,Jauho A P.Quantum Kinetics in Transport and Optics of Semiconductors[M].Berlin:Springer,2008.
[19] Sierra M A,Sanchez D.Strongly Nonlinear Thermovoltage and Heat Dissipation in Interacting Quantum Dots[J].Phys Rev B,2014,90:115313-6.DOI:10.1103/PhysRevB.90.115313.
[20] Niu P B,Wang Q,Nie Y H.Transport Through Artificial Single-Molecule Magnets:Spin-Pair State Sequential Tunneling and Kondo Effects[J].Chin Phys B,2013,22:027307-6.DOI:10.1088/1674-1056/22/2/027307.
[21] Swirkowicz R,Wierzbicki M,Barnas J.Thermoelectric Effects in Transport through Quantum Dots Attached to Ferromagnetic Leads with Noncollinear Magnetic Moments[J].Phys Rev B,2009,80:195409-10.DOI:10.1103/PhysRevB.80.195409.