晶态Ge_1Sb_4Te_7的可逆阻变新机理的第一性原理研究

First principles investigation of a new mechanism of reversible resistance switching in crystalline Ge_1Sb_4Te_7

为了改良相变存储器的工作机理,采用第一性原理计算方法进行了理论研究。结果显示,相变存储材料三元硫系化合物Ge1Sb4Te7可通过特定原子的移动实现晶体对称性的部分打破与重建,伴随着这种结构转变,其电阻率会发生显著变化。该可逆相变引起的电阻转变效应可以归因于"类三中心四电子键"的形成与断裂。这种新相变机制相对于传统的相变存储机制,具有较多优点,有利于提高相变存储器的性能。

To improve the operation mechanism of phase-change memory,we have conducted first principles calculations.The results showed that the crystal structure of phase-change material ternary chalcogenide Ge1Sb4Te7 could be partially broken and reconstructed through the motion of some specific atoms.The concomitant resistivity changes were significant.Such reversible properties transformation could be ascribed to the formation and breaking of the＂three-center four-electron like＂bonds.This new phase-change mechanism has many advantages compared with traditional mechanism.Hence,better performances of phasechange memory could be achieved.