Peierls/Su-Schrieffer-Heeger polarons in two dimensions
Peierls/Su-Schrieffer-Heeger polarons in two dimensions
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Peierls/Su-Schrieffer-Heeger 二维极化子
DOI：
10.1103/physrevb.104.035143
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发表时间：
2021
影响因子：
3.7
通讯作者：
Svistunov, Boris V.
中科院分区：
文献类型：
--
作者：
Zhang, Chao;Prokof'ev, Nikolay V.;Svistunov, Boris V.
具有不同类型电子-声子耦合的极化子具有根本不同的性质。当电子密度和晶格位移是主要相互作用时，基态动量不变，极化子在强耦合下变得指数重。与此相反，由位移调制跳变引起的一维peerls /Su-Schrieffer-Heeger （PSSH）极化子随着耦合的增加，基态动量向有限值和有效质量的中等值移动[D]。j·j·马尔尚，物理学家。通讯学报，105,266605 (2010)[j]. http://www.physrevlet.105.266605。基于图解蒙特卡罗方法，我们研究了PSSH极化子的异常性质是否取决于位移调制跳变的类型，以及它们在高维中存在的程度。我们研究了两种不同的PSSH模型：玻色子自由度驻留在二维方形晶格的点（模型A）和键（模型B）上。对于模型A，我们发现在绝热和中间状态下，基态动量作为耦合强度的函数经历了从零到有限值的连续转变。这种转变是由色散函数的二次不稳定性驱动的，这意味着有效质量在临界点处发散，然后随着耦合的增加以各向异性的方式减小。出乎意料的是，对于模型B，基态动量始终保持在零，有效质量随耦合单调增加。这种增加远不是指数级的，在强相互作用下趋于稳定，从而产生相对较轻的极化子。高温超导双极化子机制的关键在于光极化子处于强耦合区[J]。苏斯，M.查克拉博蒂，R. V.克雷姆斯和M.伯丘，物理学家。Rev. Lett.121, 247001 (2018)PRLTAO0031-900710.1103/PhysRevLett.121.247001。
Polarons with different types of electron-phonon coupling have fundamentally different properties. When the dominant interaction is between the electron density and lattice displacement, the momentum of the ground state does not change and the polaron gets exponentially heavy at strong coupling. In contrast, one-dimensional Peierls/Su-Schrieffer-Heeger (PSSH) polarons with interaction originating from displacement-modulated hopping feature a shift of the ground-state momentum to finite values and moderate values of effective mass as coupling is increased [D. J. J. Marchand , Phys. Rev. Lett. 105, 266605 (2010)PRLTAO0031-900710.1103/PhysRevLett.105.266605]. Based on Diagrammatic Monte Carlo method, we investigate whether unusual properties of PSSH polarons depend on the type of the displacement-modulated hopping and to what degree they survive in higher dimension. We study two different PSSH models: with bosonic degrees of freedom residing on sites (model A) and bonds (model B) of the two-dimensional square lattice. For model A, we find that in both adiabatic and intermediate regimes, the momentum of the ground state experiences a continuous transition from zero to a finite value as a function of coupling strength. The transition is driven by quadratic instability of the dispersion function, implying that effective mass diverges at the critical point, and then decreases in an anisotropic fashion with increasing coupling. Unexpectedly, for model B, the momentum of the ground state always stays at zero and the effective mass increases monotonously with coupling. The increase is far from exponential and tends to level off at strong interaction, resulting in relatively light polarons. Having light polarons in the strong coupling regime is crucial for the bipolaron mechanism of high-temperature superconductivity [J. Sous, M. Chakraborty, R. V. Krems, and M. Berciu, Phys. Rev. Lett. 121, 247001 (2018)PRLTAO0031-900710.1103/PhysRevLett.121.247001.]
DOI：
--
发表时间：
1974
期刊：
September 1
影响因子：
--
作者：
E. Nagaev
通讯作者：
E. Nagaev
影响因子：
--
作者：
N. Mott
通讯作者：
N. Mott
极化子运动的研究
DOI：
--
发表时间：
--
期刊：
影响因子：
--
作者：
T. Holstein
通讯作者：
T. Holstein