Tunable Valley Pseudospin\nand Electron–Phonon\nCoupling in WSe<sub>2</sub>/1T-VSe<sub>2</sub> Heterostructures

Heterostructure engineering provides versatile platforms\nfor exploring\nexotic physics and enhancing the device performance through interface\ncoupling. Despite the rich array of physical phenomena presented by\nheterostructures composed of semiconductor and metal van der Waals\nmaterials, significant gaps remain in understanding their optical,\nthermal, and electronic properties. Here, we demonstrate that the\nvalley pseudospin and electron–phonon coupling in monolayer\nWSe<sub>2</sub> are significantly influenced by interface coupling\nwith 1T-VSe<sub>2</sub>. The heterointerface alters the relaxation\nprocess of valley excitons, leading to a transition in magnetic-field-dependent\nvalley polarization from a linear to a “V” shape. Furthermore,\nwe uncover that enhanced electron–phonon coupling exacerbates\nvariations in exciton and valley exciton behavior with temperature,\ninvolving higher phonon energies and a shift from acoustic to optical\nphonons. These findings highlight a promising pathway to manipulate\nvalley excitons and investigate electron–phonon coupling through\nvan der Waals interface interactions.