Highly thermal-stable paramagnetism by rolling up MoS2 nanosheets.

Controlling phase transitions through local strain engineering is an exciting avenue for tailoring the electronic and magnetic properties of materials at the nanoscale. Herein, we demonstrate a tunable semiconducting to metallic phase transition of two-dimensional transition metal dichalcogenides using strain engineering through rolled up MoS2 sheets (named as MoS2 scrolls). A phase incorporated structure for MoS2 nanoscrolls containing the maximum concentration of 1T phase (∼58%) with high thermal stability up to 473 K can be produced by a gliding-rolling process for the S plane. These phase transitions are irreversible by virtue of the van der Waals interaction between the layers of the nanoscrolls, which is relatively stronger than the bending strain. A high concentration of the 1T phase can tune the bandgap through temperature, and also the magnetic property from nonmagnetic to paramagnetic MoS2. This study, which is able to control phase transitions by strain engineering in the field of 2D materials, proves an exciting avenue for tailoring the novel functional properties of low-dimensional materials.