Tinselenidene: a Two-dimensional Auxetic Material with Ultralow Lattice Thermal Conductivity and Ultrahigh Hole Mobility

TL;DR

This paper predicts a new 2D material, tinselenidene, with exceptional properties including ultralow thermal conductivity, ultrahigh hole mobility, and auxetic behavior, promising for thermoelectrics and nanodevices.

Contribution

It introduces a novel 2D material with unique mechanical, thermal, and electronic properties, expanding the family of 2D materials with potential technological applications.

Findings

Predicted ultralow lattice thermal conductivity (<3 W/mK) at 300 K.

Discovered ultrahigh hole mobility (~10000 cm²V⁻¹s⁻¹).

Identified large negative Poisson's ratio (-0.17).

Abstract

By means of extensive ab initio calculations, a new two-dimensional (2D) atomic material tin selenide monolayer (coined as tinselenidene) is predicted to be a semiconductor with an indirect gap (1.45 eV) and a high hole mobility (of order 10000 cm2V-1S-1), and will bear an indirect-direct gap transition under a rather low strain (<0.5 GPa). Tinselenidene has a very small Young's modulus (20-40 GPa) and an ultralow lattice thermal conductivity (<3 Wm-1K-1 at 300 K), making it probably the most flexible and most heat-insulating material in known 2D atomic materials. In addition, tinseleniden has a large negative Poisson's ratio of -0.17, thus could act as a 2D auxetic material. With these intriguing properties, tinselenidene could have wide potential applications in thermoelectrics, nanomechanics and optoelectronics.