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s*********s
发帖数: 18 | 1 graphene 研究的一个问题（请教前辈）：
graphene 在电场的gate的作用下，可以打开bandgap,i.e bilayer----- tunnable
bandgap, trilayer -----overlap band gap.
1.那么在perpendicular magnetic field 的作用下，graphene 的情况如何呢？
bandgap 能打开？ 还是打开excitonic condensation gap?还是其他情况？？
2. four-terminal graphene device 在perpendicular magnetic field 的作用下，发
现测量的电阻（不是hall effect 磁阻）线性或者非线性的随着磁场增加而增加，也就
是： R vs B， 这个如何解释？
希望前辈指教！ | s*******i
发帖数: 12823 | 2 单层graphene谁能加gate打开gap？？？
1.强磁场下当然是形成朗道能级啦，不过graphene有零能的LL，弱场下应该没有gap
2.你的磁场范围多少？弱场下Rxx当然会增加了，有magnetoresistance啊
这些很基本啊，去读读castro neto他们09年的RMP吧
【在 s*********s 的大作中提到】
: graphene 研究的一个问题（请教前辈）：
: graphene 在电场的gate的作用下，可以打开bandgap,i.e bilayer----- tunnable
: bandgap, trilayer -----overlap band gap.
: 1.那么在perpendicular magnetic field 的作用下，graphene 的情况如何呢？
: bandgap 能打开？ 还是打开excitonic condensation gap?还是其他情况？？
: 2. four-terminal graphene device 在perpendicular magnetic field 的作用下，发
: 现测量的电阻（不是hall effect 磁阻）线性或者非线性的随着磁场增加而增加，也就
: 是： R vs B， 这个如何解释？
: 希望前辈指教！
| s*********s
发帖数: 18 | 3 Thanks for your good explains and good comments.
The following responds to your one by one
单层graphene谁能加gate打开gap？？？
As mention above,i didn't mention the conclusion that monolayer graphene can
open band gap. But researcher have been shown that monolayer graphene nano-
mesh and nano-ribbon can open band gap under the applied electric field.
1.强磁场下当然是形成朗道能级啦，不过graphene有零能的LL，弱场下应该没有gap
The effect of the applied perpendicular magnetic can induce the splitting of
Landau Level and the zero-energy Level is characteristic of half filling.So
the bandstucture show discrete dispersion (splitting of Landau Level).
i want to know that the gap is band gap or excitonic gap when the
application of the magnetic field on the graphene.
My understanding is that band gap corresponds to the effect of the electric
field and the excitonic gap corresponds to the effect of the magnetic field.
2.你的磁场范围多少？弱场下Rxx当然会增加了，有magnetoresistance啊
The magnetic field range of 0-12T. The negative resistance at low field and
low temperature (weak localization effect) originates from the interval
scattering but the i want to know the origins of the non-linear magneto
resistance increase with the increasing magnetic field ( i think it is
originated from the electron-hole puddles). |
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