Penetration depth and anisotropy in MgB2 -: art. no. 172501
Penetration depth and anisotropy in MgB2 -: art. no. 172501
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DOI：
10.1103/physrevb.64.212501
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发表时间：
2001-11-01
影响因子：
3.7
通讯作者：
Chu, CW
中科院分区：
文献类型：
--
作者：
Chen, XH;Xue, YY;Chu, CW
基于各向异性t-J模型的空穴色散，计算了最佳掺杂YBa_2Cu_3 O_（7-δ）的超导转变温度Tc随a，B，c方向沿着单轴压力的变化.有一个很好的定性协议与实验。结果表明，在ab平面上，单轴压力对Tc的影响是由于空穴色散和面内对相互作用的各向异性，而在沿着c轴的单轴压缩下，Tc的降低主要是由于压力引起的CuO 2面空穴浓度的增加。分类粉末。在没有对晶粒取向进行几何校正的情况下，两组数据之间的良好一致性表明MgB_2是各向同性超导体。
The superconducting transition temperature Tc is calculated as a function of uniaxial pressure along the a, b, c directions for optimally doped YBa2Cu3O7-delta on the basis of a hole dispersion of the anisotropic t-J model. There is a good qualitative agreement with experiments. We show that the uniaxial pressure effect on T-c in the ab plane is due to the anisotropies of the hole dispersion and the in-plane pairing interaction, whereas the reduction of T-c under uniaxial compression along the c axis mainly results from the pressure-induced increase of hole concentration of the CuO2 plane.The penetration depth lambda of MgB2 was deduced from both the ac susceptibility chi and the magnetization M(H) of sorted powders. The good agreement between the two sets of data without geometric correction for the grain orientation suggests that MgB2 is an isotropic superconductor.