P-type doping in 2M-WS2 for a complete phase diagram

Abstract

2M-WS₂ as a new phase of transition metal dichalcogenides possesses many novel physical properties, such as superconductivity and topological surface states. The effect of n-type doping on the superconductivity of this material has been studied. However, p-type doping has not been studied, because it is difficult to implement p-type doping in metastable 2M-WS₂. In this paper, p-type doping was achieved in 2M-WS₂ for the first time by using Mo. With the increase of the Mo content, the carrier concentration rises slightly from 1.42 × 10²¹ cm⁻¹ to 1.56 × 10²¹ cm⁻¹. Meanwhile, the superconducting transition temperature decreases monotonously with the increase of Mo doping and reaches a minimum value of 4.37 K at the doping limit of x = 0.6 in W_1−xMo_xS₂. Combining the data of n-type doped 2M-WS₂ from our previous research, we summarize the carrier concentration and superconducting transition temperature in a phase diagram, which shows a typical dome-like shape. These results uncover the relationship between the carrier concentration and electronic state of 2M-WS₂.