Thermoelectric spin voltage in graphene 2017/12/22 - - PowerPoint PPT Presentation

Thermoelectric spin voltage in graphene

张志斌 北京大学 物理学院 2017/12/22 2017/12/22

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O u t l i n e

Seebeck Effect Spin Hall Effect Inverse Spin Hall Effect Spin Seebeck Effect

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Spin Hall Effect & Inverse Spin Hall Effect

Input charge current Output spin current Output charge current Input spin current

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Seebeck Effect

Seebeck coefficient 𝑇 = −

∆𝑊 ∆𝑈

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Spin Seebeck Effect

Uchida et al. Nature 2008

Scenario for the spin Seebeck effect: In the spin sector, a magnet works in the same way as a thermocouple

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Spin Seebeck Effect

Uchida et al. Nature 2008 Pt Ni81Fe19

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Thermoelectric spin voltage in graphene

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Thermoelectric spin voltage in graphene

Juan F. Sierra et al. Nature Nano 2017 𝑊

𝑇 = 𝑊 𝑇 + − 𝑊 𝑇 − = −∆𝑇∆𝑈 = −(𝑇2 − 𝑇1) ∆𝑈

∆𝑇 = 𝑇2(𝑜2) − 𝑇1(𝑜1)

holes electrons

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Thermoelectric spin voltage in graphene

Juan F. Sierra et al. Nature Nano 2017

Spin injection and detection @ ferromagnetic electrodes Metal electrodes

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Thermoelectric spin voltage in graphene

Juan F. Sierra et al. Nature Nano 2017 Joule heating Joule heating

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Thermoelectric spin voltage detection

Juan F. Sierra et al. Nature Nano 2017

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Out-of-plane magnetic field

Juan F. Sierra et al. Nature Nano 2017

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Thanks