标题： 锡掺杂的Bi$_{1.1}$Sb$_{0.9}$Te$_{2}$S拓扑绝缘体中量子振荡的非常规温度演化 显示英文标题

标题： Unconventional temperature evolution of quantum oscillations in Sn-doped Bi$_{1.1}$Sb$_{0.9}$Te$_{2}$S topological insulator

摘要： 在各种拓扑绝缘体中，掺锡的Bi$_{1.1}$Sb$_{0.9}$Te$_{2}$S因其卓越的性能而脱颖而出。 它具有宽能隙，并通常表现出一个与体态良好隔离的狄拉克点，费米能级位于能隙内。 我们所展示的样品表现出由于表面态导致的类似金属的低温电阻率，在40 K时仍可观测到明显的量子振荡，且费米能级大约位于狄拉克点之上100 meV处。 在本研究中，我们报告了一种异常效应：量子振荡频率具有强烈的温度依赖性，在2 K到40 K之间减少了约10%。这种减少显著超过了狄拉克准粒子的索末菲和拓扑修正预期的影响，这些修正只能解释观察到变化的八分之一。 我们将这种变化归因于电子-声子相互作用引起的体能带隙大小的温度诱导重正化，这进而影响了表面狄拉克点在能隙中的位置。 此外，我们认为在这种化合物中，表面量子振荡可以作为一种精确的工具，用于研究体能带隙大小的低温演化。 显示英文摘要

摘要： Among various topological insulators, Sn-doped Bi$_{1.1}$Sb$_{0.9}$Te$_{2}$S stands out for its exceptional properties. It has a wide energy gap and typically exhibits a well-isolated Dirac point and a Fermi level positioned within the gap. The samples we present display metallic-like low-temperature resistivity attributed to surface states, pronounced quantum oscillations observable even at 40 K, and a Fermi level located approximately 100 meV above the Dirac point. In this work, we report an unusual effect: a strong temperature dependence of the quantum oscillation frequency, which decreases by around 10\% between 2 and 40 K. This reduction significantly exceeds the expected effects of the Sommerfeld and topological corrections for Dirac quasi-particles, which could account for only one-eighth of the observed change. We attribute this change to the temperature-induced renormalization of the bulk band gap size due to electron-phonon interactions, which in turn affect the position of the surface Dirac point within the gap. Furthermore, we propose that in this compound, surface quantum oscillations can serve as a precise tool for investigating the low-temperature evolution of the bulk band gap size.