The New Phase [Tl4Sb6Se10][Sn5Sb2Se14]: A Naturally Formed Semiconducting Heterostructure with Two-Dimensional Conductance

We report on a new layered semiconductor Tl8Sn10Sb16Se48 with an indirect band gap of 0.45 eV. The novel structure is made of alternating layers of SnSe2-type [Sn5Sb2Se14] and SnSe-type [Tl4Sb6Se10]. The material exhibits two-dimensional (2D) electron variable range hopping at low temperatures, indicating an absence of interlayer coherency of the electronic state. Theoretical calculations unveil a 2D confinement for electrons in the [Sn5Sb2Se14] sheet and confirm the heterostructure nature. This unique electronic structure is attributed to the weak interlayer coupling and structure distortion in the electron-poor [Tl4Sb6Se10] layer that energetically impedes electron propagation.本研究报道了一种新型层状半导体Tl8Sn10Sb16Se48，其间接带隙为0.45电子伏特（electron Volt, eV）。该新型材料的结构由SnSe2型[Sn5Sb2Se14]与SnSe型[Tl4Sb6Se10]交替堆叠的层状结构构成。该材料在低温下表现出二维（2D）电子变程跳跃行为，表明其电子态不存在层间相干性。理论计算揭示了[Sn5Sb2Se14]片层中电子的二维限域效应，并证实了该材料的异质结构特性。这种独特的电子结构源于贫电子[Tl4Sb6Se10]层中的弱层间耦合与结构畸变，后者在能量层面阻碍了电子的传输。