Modified Kedem-Katchalsky equations for osmosis through nano-pore

This work presents a modified Kedem-Katchalsky equations for osmosis through nano-pore. osmotic reflection coefficient of a solute was found to be chiefly affected by the entrance of the pore while filtration reflection coefficient can be affected by both the entrance and the internal structure of the pore. Using an analytical method, we get the quantitative relationship between osmotic reflection coefficient and the molecule size. The model is verified by comparing the theoretical results with the reported experimental data of aquaporin osmosis. Our work is expected to pave the way for a better understanding of osmosis in bio-system and to give us new ideas in designing new membranes with better performance.Comment: 19 pages, 4 figure

Verification of Onsager reciprocal relation between anomalous transverse coefficients of an anisotropic antiferromagnet

Whenever two irreversible processes occur simultaneously, time-reversal symmetry of microscopic dynamics gives rise, on a macroscopic level, to Onsager's reciprocal relations, which impose constraints on the number of independent components of any transport coefficient tensor. Here, we show that in the antiferromagnetic YbMnBi$_2$, which displays a strong temperature-dependent anisotropy, the Onsager's reciprocal relations are strictly satisfied for anomalous electric, $\sigma^A_{ij}$, and anomalous thermoelectric, $\alpha^A_{ij}$, conductivity tensors. In contradiction with what was recently reported by Pan [1], we find that $\sigma^A_{ij} (H)= \sigma^A_{ji} (-H)$, and $\alpha^A_{ij} (H)= \alpha^A_{ji} (-H)$. This equality holds in the whole temperature window irrespective of the relative weights of the intrinsic or extrinsic mechanisms. The $\alpha^A_{ij}/\sigma^A_{ij}$ ratio is close $k_B/e$ at room temperature, but peaks to an unprecedented magnitude of 2.9 $k_B/e$ at $\sim$ 150 K, which may involve non-degenerate carriers of small Fermi surface pockets.Comment: 6 pages, 4 figures,supplemental materials include

Phonon thermal Hall effect in strontium titanate

It has been known for more than a decade that phonons can produce an off-diagonal thermal conductivity in presence of magnetic field. Recent studies of thermal Hall conductivity, $\kappa_{xy}$, in a variety of contexts, however, have assumed a negligibly small phonon contribution. We present a study of $\kappa_{xy}$ in quantum paraelectric SrTiO$_3$, which is a non-magnetic insulator and find that its peak value exceeds what has been reported in any other insulator, including those in which the signal has been qualified as 'giant'. Remarkably, $\kappa_{xy}(T)$ and $\kappa(T)$ peak at the same temperature and the former decreases faster than the latter at both sides of the peak. Interestingly, in the case of La$_2$CuO$_4$ and $\alpha$-RuCl$_3$, $\kappa_{xy}(T)$ and $\kappa(T)$ peak also at the same temperature. We also studied KTaO$_3$ and found a small signal, indicating that a sizable $\kappa_{xy}(T)$ is not a generic feature of quantum paraelectrics. Combined to other observations, this points to a crucial role played by antiferrodistortive domains in generating $\kappa_{xy}$ of this solid.Comment: Main text: 6 pages, 4 figures, Supplemental Material is included. Accepted by Phys. Rev. Let