Browsing by Author "Liu, Hui"

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    Exchange field enhanced upper critical field of the superconductivity in compressed antiferromagnetic EuTe2
    (Springer Nature, 2023) Sun, Hualei; Qiu, Liang; Han, Yifeng; Zhang, Yunwei; Wang, Weiliang; Huang, Chaoxin; Liu, Naitian; Huo, Mengwu; Li, Lisi; Liu, Hui; Liu, Zengjia; Cheng, Peng; Zhang, Hongxia; Wang, Hongliang; Hao, Lijie; Li, Man-Rong; Yao, Dao-Xin; Hou, Yusheng; Dai, Pengcheng; Wang, Meng; Rice Center for Quantum Materials
    Understanding the interplay between superconductivity and magnetism has been a longstanding challenge in condensed matter physics. Here we report high pressure studies on the C-type antiferromagnetic semiconductor EuTe2 up to 36.0 GPa. A structural transition from the I4/mcm to the C2/m space group is identified at ~16 GPa. Superconductivity is observed above ~5 GPa in both structures. In the low-pressure phase, magnetoresistance measurements reveal strong couplings between the local moments of Eu2+ and the conduction electrons of Te 5p orbits. The upper critical field of superconductivity is well above the Pauli limit. While EuTe2 becomes nonmagnetic in the high-pressure phase and the upper critical field drops below the Pauli limit. Our results demonstrate that the high upper critical field of EuTe2 in the low-pressure phase is due to the exchange field compensation effect of Eu2+ and the superconductivity in both structures may arise in the framework of the Bardeen-Cooper-Schrieffer theory.
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    Lysyl hydroxylase 2 induces a collagen cross-link switch in tumor stroma
    (American Society for Clinical Investigation, 2015) Chen, Yulong; Terajima, Masahiko; Yang, Yanan; Sun, Li; Ahn, Young-Ho; Pankova, Daniela; Puperi, Daniel S.; Watanabe, Takeshi; Kim, Min P.; Blackmon, Shanda H.; Rodriguez, Jaime; Liu, Hui; Behrens, Carmen; Wistuba, Ignacio I.; Minelli, Rosalba; Scott, Ken
    Epithelial tumor metastasis is preceded by an accumulation of collagen cross-links that heighten stromal stiffness and stimulate the invasive properties of tumor cells. However, the biochemical nature of collagen cross-links in cancer is still unclear. Here, we postulated that epithelial tumorigenesis is accompanied by changes in the biochemical type of collagen cross-links. Utilizing resected human lung cancer tissues and a p21CIP1/WAF1-deficient, K-rasG12D-expressing murine metastatic lung cancer model, we showed that, relative to normal lung tissues, tumor stroma contains higher levels of hydroxylysine aldehyde–derived collagen cross-links (HLCCs) and lower levels of lysine aldehyde–derived cross-links (LCCs), which are the predominant types of collagen cross-links in skeletal tissues and soft tissues, respectively. Gain- and loss-of-function studies in tumor cells showed that lysyl hydroxylase 2 (LH2), which hydroxylates telopeptidyl lysine residues on collagen, shifted the tumor stroma toward a high-HLCC, low-LCC state, increased tumor stiffness, and enhanced tumor cell invasion and metastasis. Together, our data indicate that LH2 enhances the metastatic properties of tumor cells and functions as a regulatory switch that controls the relative abundance of biochemically distinct types of collagen cross-links in the tumor stroma.
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    Single-crystal growth and superconductivity in RbNi2Se2
    (American Physical Society, 2022) Liu, Hui; Hu, Xunwu; Guo, Hanjie; Teng, Xiao-Kun; Bu, Huanpeng; Luo, Zhihui; Li, Lisi; Liu, Zengjia; Huo, Mengwu; Liang, Feixiang; Sun, Hualei; Shen, Bing; Dai, Pengcheng; Birgeneau, Robert J.; Yao, Dao-Xin; Yi, Ming; Wang, Meng
    We report the synthesis and characterization of RbNi2Se2, an analog of the iron chalcogenide superconductor RbxFe2Se2, via transport, angle-resolved photoemission spectroscopy, and density functional theory calculations. A superconducting transition at Tc=1.20 K is identified. In the normal state, RbNi2Se2 shows paramagnetic and Fermi-liquid behaviors. A large Sommerfeld coefficient yields an effective electron mass of m∗≈6me. In the superconducting state, zero-field electronic specific-heat data Ces can be described by a two-gap BCS model, indicating that RbNi2Se2 is a possible multigap superconductor. Our density functional theory calculations and angle-resolved photoemission spectroscopy measurements demonstrate that RbNi2Se2 exhibits relatively weak correlations and multiband characteristics, consistent with the multigap superconductivity.