Feature: plot sts_line_ave

Author: YuLiu98

tools/stm/stm.py

@@ -123,7 +123,7 @@ def scan2(self, bias, z, repeat=(1, 1)):
         # Returing scan with axes in Angstrom.
         return x, y, current
 
-    
+
     def linescan(self, bias, current, p1, p2, npoints=50, z0=None):
         """Constant current line scan.
 
@@ -225,6 +225,30 @@ def line_sts(self, bias0, bias1, biasstep, p1, p2, npoints=50):
         return biases, np.linspace(0, s, npoints), current, dIdV
 
 
+    def line_sts_ave(self, bias0, bias1, biasstep, npoints=50):
+
+        biases = np.arange(bias0, bias1 + biasstep, biasstep)
+        current = np.zeros((npoints, len(biases)))
+
+        for b in np.arange(len(biases)):
+            print(b, biases[b])
+            self.read_ldos(biases[b])
+            nz = self.ldos.shape[2]
+
+            for i in range(npoints):
+                z = i / (npoints - 1) * nz
+                dz = z - np.floor(z)
+                z = int(z) % nz
+                current[i, b] = ((1 - dz) * self.ldos[:, :, z].mean() +
+                    dz * self.ldos[:, :, (z + 1) % nz].mean())
+            
+        dIdV = np.zeros((npoints, len(biases)))
+        for i in range(npoints):
+            dIdV[i, :] = np.gradient(current[i, :], biasstep)
+
+        return biases, np.linspace(0, 1, npoints), current, dIdV
+
+
     def find_current(self, ldos, z):
         """ Finds current for given LDOS at height z."""
         nz = self.ldos.shape[2]
@@ -279,4 +303,4 @@ def find_height(ldos, current, h, z0=None):
 def delta(biases, bias, width):
     """Return a delta-function centered at 'bias'"""
     x = -((biases - bias) / width)**2
-    return np.exp(x) / (np.sqrt(np.pi) * width)
+    return np.exp(x) / (np.sqrt(np.pi) * width)