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1. Controlling Stoichiometry in Ultrathin van der Waals Films: PtTe ₂ , Pt ₂ Te ₃ , Pt ₃ Te ₄ , and Pt ₂ Te ₂

   https://doi.org/10.1021/acsnano.2c04303  

   Lasek, Kinga; Ghorbani-Asl, Mahdi; Pathirage, Vimukthi; Krasheninnikov, Arkady V.; Batzill, Matthias (June 2022, ACS Nano)
2. Delicate Ferromagnetism in MnBi ₆ Te ₁₀

   https://doi.org/10.1021/acs.nanolett.2c02500  

   Yan, Chenhui; Zhu, Yanglin; Miao, Leixin; Fernandez-Mulligan, Sebastian; Green, Emanuel; Mei, Ruobing; Tan, Hengxin; Yan, Binghai; Liu, Chao-Xing; Alem, Nasim; et al (October 2022, Nano Letters)
3. Monolayer Superconductivity and Tunable Topological Electronic Structure at the Fe(Te,Se)/Bi ₂ Te ₃ Interface

   https://doi.org/10.1002/adma.202210940  

   Moore, Robert_G; Lu, Qiangsheng; Jeon, Hoyeon; Yao, Xiong; Smith, Tyler; Pai, Yun‐Yi; Chilcote, Michael; Miao, Hu; Okamoto, Satoshi; Li, An‐Ping; et al (April 2023, Advanced Materials)

   Abstract The interface between 2D topological Dirac states and ans‐wave superconductor is expected to support Majorana‐bound states (MBS) that can be used for quantum computing applications. Realizing these novel states of matter and their applications requires control over superconductivity and spin‐orbit coupling to achieve spin‐momentum‐locked topological interface states (TIS) which are simultaneously superconducting. While signatures of MBS have been observed in the magnetic vortex cores of bulk FeTe_0.55Se_0.45, inhomogeneity and disorder from doping make these signatures unclear and inconsistent between vortices. Here superconductivity is reported in monolayer (ML) FeTe_1–ySe_y(Fe(Te,Se)) grown on Bi₂Te₃by molecular beam epitaxy (MBE). Spin and angle‐resolved photoemission spectroscopy (SARPES) directly resolve the interfacial spin and electronic structure of Fe(Te,Se)/Bi₂Te₃heterostructures. Fory = 0.25, the Fe(Te,Se) electronic structure is found to overlap with the Bi₂Te₃TIS and the desired spin‐momentum locking is not observed. In contrast, fory = 0.1, reduced inhomogeneity measured by scanning tunneling microscopy (STM) and a smaller Fe(Te,Se) Fermi surface with clear spin‐momentum locking in the topological states are found. Hence, it is demonstrated that the Fe(Te,Se)/Bi₂Te₃system is a highly tunable platform for realizing MBS where reduced doping can improve characteristics important for Majorana interrogation and potential applications. 

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4. In ₂ Se ₃ , In ₂ Te ₃ , and In ₂ (Se,Te) ₃ Alloys as Photovoltaic Materials

   https://doi.org/10.1021/acs.jpclett.2c02975  

   Li, Wei; Cai, Xue-Fen; Valdes, Nicholas; Wang, Tianshi; Shafarman, William; Wei, Su-Huai; Janotti, Anderson (December 2022, The Journal of Physical Chemistry Letters)
5. Systemic consequences of disorder in magnetically self-organized topological MnBi ₂ Te ₄ /(Bi ₂ Te ₃ ) _n superlattices

   https://doi.org/10.1088/2053-1583/ac3cc6  

   Sitnicka, Joanna; Park, Kyungwha; Skupiński, Paweł; Grasza, Krzysztof; Reszka, Anna; Sobczak, Kamil; Borysiuk, Jolanta; Adamus, Zbigniew; Tokarczyk, Mateusz; Avdonin, Andrei; et al (December 2021, 2D Materials)

   Abstract MnBi 2 Te 4 /(Bi 2 Te 3 ) n materials system has recently generated strong interest as a natural platform for the realization of the quantum anomalous Hall (QAH) state. The system is magnetically much better ordered than substitutionally doped materials, however, the detrimental effects of certain disorders are becoming increasingly acknowledged. Here, from compiling structural, compositional, and magnetic metrics of disorder in ferromagnetic (FM) MnBi 2 Te 4 /(Bi 2 Te 3 ) n it is found that migration of Mn between MnBi 2 Te 4 septuple layers (SLs) and otherwise non-magnetic Bi 2 Te 3 quintuple layers (QLs) has systemic consequences—it induces FM coupling of Mn-depleted SLs with Mn-doped QLs, seen in ferromagnetic resonance as an acoustic and optical resonance mode of the two coupled spin subsystems. Even for a large SL separation ( n ≳ 4 QLs) the structure cannot be considered as a stack of uncoupled two-dimensional layers. Angle-resolved photoemission spectroscopy and density functional theory studies show that Mn disorder within an SL causes delocalization of electron wave functions and a change of the surface band structure as compared to the ideal MnBi 2 Te 4 /(Bi 2 Te 3 ) n . These findings highlight the critical importance of inter- and intra-SL disorder towards achieving new QAH platforms as well as exploring novel axion physics in intrinsic topological magnets. 

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