ABSTRACT
Opening up a band gap without lowering high carrier mobility in germanene and finding suitable substrate materials to form van der Waals heterostructures have recently emerged as an intriguing way of designing a new type of electronic devices. By using first-principles calculations, here, we systematically investigate the effect of the GaGeTe substrate on the electronic properties of monolayer germanene. Linear dichroism of the Dirac-cone like band dispersion and higher carrier mobility (9.7 × 103 cm2 V-1 s-1) in the Ge/GaGeTe heterostructure (HTS) are found to be preserved compared to that of free-standing germanene. Remarkably, the band structure of HTS can be flexibly modulated by applying bias voltage or strain. A prototype data storage device FET based on Ge/GaGeTe HTS is proposed, which presents a promising high performance platform with a tunable band gap and high carrier mobility.
ABSTRACT
Based on first-principles calculations, we study the structural, electronic, and magnetic properties of two-dimensional silicene saturated with hydrogen and bromine atoms. It is found that the fully saturated silicene exhibits nonmagnetic semiconducting behavior, while half-saturation on only one side with hydrogen or bromine results in the localized and unpaired electrons of the unsaturated Si atoms, showing ferromagnetic semiconducting or half-metallic properties, respectively. Total energy calculations show that the half-hydrogenated silicene exhibits a ferromagnetic order, while the half-brominated one exhibits an antiferromagnetic behavior.
ABSTRACT
Based on first-principles calculations, the geometric, electronic, and magnetic properties as well as the relative stability of the fully hydrogenated and semihydrogenated AlN nanosheets (NSs) have been investigated. The results show that different with the bare graphite-like AlN NSs terminating with polar (0001) surfaces, the hydrogenated configurations preserve the initial wurtzite structure. Depending on surface hydrogenation and the thickness of AlN NSs, three magnetic configurations, that is, semiconductor, half metal, and metal states, are all observed. Analysis of formation energies indicates that, for the configuration n = 1, the hydrogen atoms adsorb on the top of Al sites is the most stable structure, while for the other configurations (n > 2), AlN-nH structure is more favorable energetically. The results indicated that hydrogenation on different Al and N sites might be an efficient route to tune their electronic and magnetic properties to realize potential applications in the fields of electronics and spintronics.