Memory device

A memory device, comprising:

• a memory cell including a first conductive layer, a second conductive layer, a switching layer provided between the first conductive layer and the second conductive layer, and a variable resistance layer provided between the switching layer and the second conductive layer, the memory cell having an electrical resistance changing with application of a predetermined voltage and having a low resistance state and a high resistance state having a higher electrical resistance than in the low resistance state,
• wherein the switching layer contains at least one first compound selected from a group consisting of molybdenum disulfide, molybdenum diselenide, molybdenum ditelluride, tungsten disulfide, tungsten diselenide, indium selenide, gallium sulfide, gallium selenide, gallium telluride, germanium sulfide, germanium selenide, germanium telluride, silicon sulfide, silicon selenide, silicon telluride, tin sulfide, tin selenide, tin telluride, rhenium disulfide, rhenium diselenide, and rhenium ditelluride,
• the first conductive layer contains at least one second compound selected from a group consisting of tungsten ditelluride, titanium disulfide, titanium diselenide, tantalum disulfide, tantalum diselenide, niobium disulfide, niobium diselenide, hafnium disulfide, and hafnium diselenide, graphene, or graphite, and
• when the memory cell is in the low resistance state, if a voltage is applied between the first conductive layer and the second conductive layer, a nonlinear current-voltage characteristic that a current increases at a first threshold voltage appears as an absolute value of the voltage increases, and a current-voltage characteristic that a current decreases at a first voltage having an absolute value smaller than that of the first threshold voltage appears as the absolute value of the voltage decreases from a voltage exceeding the first threshold voltage.

A memory device, comprising:

• a memory cell including a first conductive layer, a second conductive layer, and a memory layer provided between the first conductive layer and the second conductive layer and having a characteristic that a threshold voltage changes, a current increasing at the threshold voltage by application of a predetermined voltage, and the memory cell having a low resistance state and a high resistance state having a higher electrical resistance than in the low resistance state,
• wherein the memory layer contains at least one first compound selected from a group consisting of molybdenum disulfide, molybdenum diselenide, molybdenum ditelluride, tungsten disulfide, tungsten diselenide, indium selenide, gallium sulfide, gallium selenide, gallium telluride, germanium sulfide, germanium selenide, germanium telluride, silicon sulfide, silicon selenide, silicon telluride, tin sulfide, tin selenide, tin telluride, rhenium disulfide, rhenium diselenide, and rhenium ditelluride,
• at least one of the first conductive layer and the second conductive layer contains at least one second compound selected from a group consisting of tungsten ditelluride, titanium disulfide, titanium diselenide, tantalum disulfide, tantalum diselenide, niobium disulfide, niobium diselenide, hafnium disulfide, and hafnium diselenide, graphene, or graphite, and
• when the memory cell is in the low resistance state, if a voltage is applied between the first conductive layer and the second conductive layer, a nonlinear current-voltage characteristic that a current increases at a first threshold voltage appears as an absolute value of the voltage increases, and a current-voltage characteristic that a current decreases at a first voltage having an absolute value smaller than that of the first threshold voltage appears as the absolute value of the voltage decreases from a voltage exceeding the first threshold voltage.