奈尔温度模拟设置

[IMPLICIT-NONE]

您好，非常感谢您提供这么好用的软件。想请教一下，对于反铁磁材料奈尔温度的模拟，应该怎么设置参数？ 似乎单纯更改格点的磁矩正负值和 J 的正负值，不能给出合理的结果。

[golddoushi]

设置好初始自旋与J即可模拟反铁磁。需要注意的是最后输出的平均自旋是平均到sublattice上的自旋，所以可能不为零。单纯找Neel温度一般只需要找比热峰值即可。 下面是一个简单正方格子双轨道的反铁磁系统的设置参数，供您参考。您可以保存在txt文件中然后用最新版的mcsolver加载并运行。

This is mcsolver's save file, version: 2.2 Lattice: 1.000000000 0.000000000 0.000000000 0.000000000 1.000000000 0.000000000 0.000000000 0.000000000 1.000000000 Supercell used in MC simulations: 16 16 1 Orbitals in cell: 2 Postions, initial spin states and onsite-anisotropy of every orbitals: orb 0: type 0 spin 1.000000000 pos [0.000000000 0.000000000 0.000000000] Dx 0.000000000 Dy 0.000000000 Dz 0.000000000 h 0.000000000 orb 1: type 0 spin -1.000000000 pos [0.500000000 0.500000000 0.000000000] Dx 0.000000000 Dy 0.000000000 Dz 0.000000000 h 0.000000000 Bonds: 4 id, source, target, overLat, exchange matrix elements of each bond: bond 0: Jx 1.000000000 Jy 1.000000000 Jz 1.000000000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [0 0 0] bond 1: Jx 1.000000000 Jy 1.000000000 Jz 1.000000000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [-1 -1 0] bond 2: Jx 1.000000000 Jy 1.000000000 Jz 1.000000000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [-1 0 0] bond 3: Jx 1.000000000 Jy 1.000000000 Jz 1.000000000 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [0 -1 0] Temperature scanning region: Tmin 2.000000000 Tmax 3.000000000 nT 8 Field scanning region: Hmin 0.000000000 Hmax 0.100000000 nH 1 Dipole long-range coupling: alpha 0.000000 Mesurement: mesure the correlation function between orb0 and orb0 over [0 0 0] Supergroup OrbGroup:1 Supergroup group0 orb0-orb0 Distribution output frame: 0 Sweeps for thermalization and statistics, and relaxiation step for each sweep: 40000 80000 1 XAxis type: T Model type: Ising Algorithm: Wolff Ncores: 4

[PG13s]

老师您好，我尝试把CrI3的例子改成AFM，计算奈尔温度，但输出的结果仍是铁磁居里温度，麻烦老师看下问题在哪，谢谢！ 输入文件： This is mcsolver's save file, version: 2.3 Lattice: 1.000000000 0.000000000 0.000000000 -0.500000000 0.866025404 0.000000000 0.000000000 0.000000000 1.000000000 Supercell used in MC simulations: 16 16 1 Orbitals in cell: 2 Positions, initial spin states and onsite-anisotropy of every orbital: orb 0: type 0 spin 1.500000000 pos [0.333333333 0.666666667 0.000000000] Dx 0.000000000 Dy 0.000000000 Dz 0.000000000 h 0.000000000 orb 1: type 0 spin -1.500000000 pos [0.666666667 0.333333333 0.000000000] Dx 0.000000000 Dy 0.000000000 Dz 0.000000000 h 0.000000000 Bonds: 3 id, source, target, overLat, exchange matrix elements of each bond: bond 0: Jx 15.700438500 Jy 15.700438500 Jz 15.700438500 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [0 0 0] bond 1: Jx 15.700438500 Jy 15.700438500 Jz 15.700438500 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [-1 0 0] bond 2: Jx 15.700438500 Jy 15.700438500 Jz 15.700438500 Jxy 0.000000000 Jxz 0.000000000 Jyz 0.000000000 Jyx 0.000000000 Jzx 0.000000000 Jzy 0.000000000 orb 0 to orb 1 over [0 1 0] Temperature scanning region: Tmin 4.000000000 Tmax 80.000000000 nT 20 Field scanning region: Hmin 0.000000000 Hmax 0.100000000 nH 1 Dipole long-range coupling: alpha 0.000000 Measurement: measure the correlation function between orb0 and orb0 over [0 0 0] Supergroup OrbGroup:1 Supergroup group0 orb0-orb0 Distribution output frame: 0 Sweeps for thermalization and statistics, and relaxiation step for each sweep: 40000 80000 0 XAxis type: T Model type: Ising Algorithm: Metropolis Ncores: 2

输出结果：

Temp # # #Susc #energy #capacity #Binder cumulante #auto-corr.

4.000 1.499916 1.499916 0.000063 0.006349 0.000164 0.999998 -0.000028 8.000 1.499916 1.499916 0.000031 0.006358 0.000041 0.999998 -0.000028 12.000 1.499915 1.499915 0.000021 0.006444 0.000019 0.999998 -0.000028 16.000 1.499911 1.499911 0.000017 0.006700 0.000011 0.999998 -0.000028 20.000 1.499904 1.499904 0.000014 0.006903 0.000007 0.999998 -0.000028 24.000 1.499474 1.499474 0.000066 0.035376 0.000026 0.999989 -0.000026 28.000 1.497982 1.497982 0.000216 0.129978 0.000073 0.999957 -0.000018 32.000 1.494022 1.494022 0.000559 -0.047738 0.000165 0.999861 0.000007 36.000 1.485831 1.485831 0.001175 0.001742 0.000305 0.999636 0.000077 40.000 1.468821 1.468821 0.002314 0.030784 0.000530 0.999039 0.000294 44.000 1.437776 1.437776 0.004155 -0.101400 0.000844 0.997550 0.000894 48.000 1.372842 1.372842 0.007610 2.330761 0.001420 0.990432 0.004288 52.000 1.184647 1.184647 0.016281 2.611736 0.002759 0.920974 1.239066 56.000 0.718141 0.718141 0.030969 -4.615790 0.003018 0.630794 0.636608 60.000 0.404567 0.404567 0.034772 -1.180485 0.001675 0.452646 0.231827 64.000 0.265853 0.265853 0.034052 -1.156174 0.001169 0.375992 0.104709 68.000 0.216890 0.216890 0.032396 -0.328044 0.000981 0.347624 0.069588 72.000 0.183535 0.183535 0.030782 2.594221 0.000809 0.350610 0.048272 76.000 0.160189 0.160189 0.029268 3.027627 0.000694 0.341673 0.035824 80.000 0.145966 0.145966 0.027859 3.547126 0.000615 0.338757 0.028863

[golddoushi]

@PG13s CrI3这种bilattice反铁磁模型与铁磁可以通过一个gauge变化对偶，所以具有相同的相变温度

[PG13s]

@PG13s CrI3这种bilattice反铁磁模型与铁磁可以通过一个gauge变化对偶，所以具有相同的相变温度

感谢老师的回复，还想问下，如果是反铁磁的情形，软件能否读取双格点原胞的总自旋期望，目前软件输出的第2,3列Si和Sj总是同一个数值，理应低温时Sj有负号，谢谢！