ABSTRACT
In multivalley systems, the valley pseudospin offers rich physics going from encoding of information by its polarization (valleytronics), to exploring novel phases of matter when its degeneracy is changed. Here, by strain engineering, we reveal fully valley-polarized quantum Hall phases in the Pb_{1-x}Sn_{x}Se Dirac system. Remarkably, when the valley energy splitting exceeds the fundamental band gap, we observe a "bipolar quantum Hall phase," heralded by the coexistence of hole and electron chiral edge states at distinct valleys in the same quantum well. This suggests that spatially overlaid counterpropagating chiral edge states emerging at different valleys do not interfere with each other.
ABSTRACT
Discussed is a 34-year-old man who hospitalized for manifesting the superior vena cava syndrome. Chest radiograph and chest CT scan revealed a gross tumor shadow in the superior mediastinum and a tiny shadow in the right lung. Superior vena cavography showed intimal stenosis, irregularities, and stiffness of the superior vena cava. Thus, radiotherapy applied to primary lesion of the mediastinum was provided to relieve his complaints. One year later, predominant metastatic pulmonary lesions and skin lesions developed. Light and electron microscopic findings of a biopsied specimen of the skin lesion were consistent with leiomyosarcoma. CYVADIC combination chemotherapy reduced the pulmonary metastatic lesions dramatically. The literature of mediastinal leiomyosarcoma is reviewed and the origin of this tumor is discussed.
