Interface-engineered enhancement of the Nernst response in Pt/graphene/YIG heterostructures

Pt/グラフェン/YIGヘテロ構造における界面エンジニアリングによるネルンスト応答の増大

Choi, J. W.*; 吉川 貴史; Lee, S.-K.*; 他11名*

Choi, J. W.*; Kikkawa, Takashi; Lee, S.-K.*; 11 of others*

The Nernst effect enables the conversion of a temperature gradient into a transverse electrical voltage and provides a planar approach to thermoelectric energy conversion. Here, we report an enhanced transverse Nernst response in Pt/graphene (Gr)/YFeO (YIG)/GdGaO (GGG) heterostructures at room temperature. Systematic comparisons with Pt/TiSe/Gr/YIG/GGG, Pt/ZrSe/Gr/YIG/GGG, Pt/YIG/GGG, Pt/Gr/GGG, and Pt/GGG show that the pronounced interface-associated contribution requires the combined Pt/Gr/YIG architecture. The control structures further demonstrate that neither the Pt/Gr conducting channel in the absence of YIG nor direct Pt/YIG contact reproduces the enhanced response. First-principles model calculations show that the graphene-derived electronic structure is sensitive to direct Pt-Gr hybridization, interfacial separation, spacer insertion, and an imposed magnetic exchange perturbation. These findings support an interface-engineered anomalous thermoelectric response and suggest that spin-orbit-coupled interfacial band reconstruction may provide a possible microscopic pathway toward Berry-curvature-related transverse transport.