Hanqi Pi

Nov 29, 2024 | nature.com | Hanqi Pi |Hongming Weng

AbstractThe origin of resistivity peak and sign reversal of Hall resistivity in ZrTe5 has long been debated. Despite various theories proposed to explain these unique transport properties, there’s a lack of comprehensive first principles studies. In this work, we employ first principles calculations and Boltzmann transport theory to explore transport properties of narrow-gap semiconductors across varying temperatures and doping levels within the relaxation time approximation.

Jun 14, 2024 | link.aps.org | Hanqi Pi |Sitaram Ramakrishnan |Surya Rohith Kotla

At ambient conditions adopts the structure type with space group . It undergoes a charge-density-wave (CDW) transition at  K, followed by a structural transition at  K. Temperature-dependent single-crystal x-ray diffraction (SXRD) leads to the observation of incommensurate superlattice reflections at with at 200 K. The CDW has orthorhombic symmetry with the noncentrosymmetric superspace group , where is a subgroup of as well as of .

Mar 18, 2024 | nature.com | Hanqi Pi |Lin Li |Rong Zhang |Hongming Weng |Changgan Zeng |Xianyang Lu

AbstractThe magnetic type-II Weyl semimetal (MWSM) Co3Sn2S2 has recently been found to host a variety of remarkable phenomena including surface Fermi-arcs, giant anomalous Hall effect, and negative flat band magnetism. However, the dynamic magnetic properties remain relatively unexplored. Here, we investigate the ultrafast spin dynamics of Co3Sn2S2 crystal using time-resolved magneto-optical Kerr effect and reflectivity spectroscopies.

Aug 24, 2023 | link.aps.org | Optoelectronics Engineering |Xin Han |Hanqi Pi

Xin Han (韩鑫)1,2,*, Hanqi Pi (皮涵琦)1,3,*, Dayu Yan (闫大禹)1,*, Ruihan Zhang (张锐涵)1,3, Yong Li (李勇)1,2, Xiang Wang (王翔)1,3, Zhiling Dun (顿志凌)1,†, Zhijun Wang (王志俊)1,3, Hai L.

Apr 10, 2023 | link.aps.org | Tianchen Hu |Hanqi Pi |Shuxiang Xu

Abstract In condensed matter physics, materials with kagome lattice display a range of exotic quantum states, including charge density wave (CDW), superconductivity, and magnetism. Recently, the intermetallic kagome metal ScV6Sn6 was discovered to undergo a first-order structural phase transition with the formation of a 3×3×3 CDW at around 92 K. The bulk electronic band properties are crucial to understanding the origin of the structural phase transition.