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.