Giant Seebeck coefficient of high density 2DEG confined within a SrTiO₃ unit cell layer

Abstract

We demonstrate that a high-density 2DEG that is confined within a unit cell layer thickness in SrTiO₃ yields an enhanced ZT_2DEG value exceeding 2. In the optimized case, the |S| value for the 2D confined ne of 1.4×10²¹ cm^-3 is 850 μV⋅K^-1, which is ∼5 times larger than that of the 3D-bulk SrTiO₃ (170 μV⋅K^-1), while the 2DEG system retains the rather high σ_2DEG value of 1.4×10³ S⋅cm^-1, leading to a ZT_2DEG value of ∼2.4 at room temperature if κ value of bulk single crystal SrTiO₃ is used for the calculation.